Forensics Final Exam
parts of the compound microscope - stage
3. The horizontal plate on which the specimens are placed for study. The specimens are normally mounted on glass slides that are held firmly in place on the stage by spring clips.
CODIS
FBI's Combined DNA Index System; enables federal, state, and local crime laboratories to electronically exchange and compare DNA profiles; national database of DNA profiles using 13 core STR
glass fragments can be analyzed by _____ for additional discrimination information.
ICP-MS
chemical and analytical tests for gunpowder residue on garments
IR photograph, Griess Test, Rhodizonate Test, Diphenylamine color test, application of an adhesive tape or adhesive to the hand's surface, swabbing both the firing and nonfiring hands with cotton that has been moistened with 5 percent nitric acid
natural fibers
Fibers derived entirely from animal or plant sources. Include hair coverings from animlas like sheep (wool), goats (mohair, cashmere),... Same procedure as hair examination. Standard/reference samples. Most prevalent Cotton.
manufactured fibers
Fibers derived from either natural or synthetic polymers; the fibers are typically made by forcing the polymeric material through the holes of a spinneret. Rayon, 1911, Nylon, 1939.
heterozygous alleles on a DNA profile
Heterozygous: A gene pair made of two different genes Example: 15, 16 (at some STR)
calculate allele frequencies at a locus
Homozygote • 11,11 at D13S317 locus Frequency of allele 11:0.33940 Frequency at locus= (0.33940)2= 0.11519 Heterozygote • 10,11 at D7S820 locus Frequency of allele 10:0.24338 Frequency of allele 11:0.20695 Frequency at locus:= (2) x (0.24338) x (0.20695)= 0.10073
A technique for visualizing latent fingerprints on non-porous surfaces by exposing them to cyanoacrylate vapors is
SuperGlue® fuming
The structure of DNA requires the pairing of base A to _____ and base G to _____.
T, C
monomer
The basic unit of structure from which a polymer is constructed.
amino acids
The building blocks of proteins; there are twenty common amino acids; amino acids are linked to form a protein; the types of amino acids and the order in which they're linked determine the character of each protein.
type of knot
can tell a tale - was another individual present?
the presence of what element differentiates organic compounds from inorganic compounds?
carbon
firearm, knives, glass
cardboard box
A pattern created when blood-covered object flings blood in an arc onto a surface is known as _____.
cast-off
forensic/medicolegal autopsy
determine the cause of death and manner of death for legal/criminal purposes (external and internal analysis of the body)
firearms identification
determining whether a bullet or cartridge was fired by a particular gun
Sir Alec Jeffreys
developed the first DNA profiling test in 1984
In the RFLP DNA typing process , DNA fragments can be visualized on an agarose gel in a process called
electrophoresis
lifting and preserving dust impressions is often accomplished using _____.
electrostatic lifting
excretion
elimination of alcohol from the body in an unchanged state, alcohol is normally excreted in breath, urine and perspiration. - exhaled in the breath direct proportional to blood concentration - "burn-off" rate 0.015% w/v per hour - varies 30% among individuals
light emitted from a source and separated into its component colors or frequencies?
emission spectra
individual characteristics
evidence that can be associated with a common source with an extremely high degree of probability (fingerprints, handwriting, torn material that fits like a puzzle, striation markings on bullets)
real evidence
evidence that consists of physical material or traces of physical activity
The basic principles behind fingerprint identification are individual characteristics, fingerprints remain unchanged through an individual's lifetime and
fingerprints may be systematically classified based on general ridge patterns
patent/visible prints
fingers touching a surface after the ridges have been in contact with a colored material such as blood, paint, grease, ink
forensic analysis of glass
flotation and immersion method
the phases of hair growth include all of the following except
follicagen
the _____ is a translucent piece of tissue surrounding the hair's shaft and contains DNA.
follicular tag
gauge
for shotguns the terms "gauge" is used
plain arch
formed by ridges entering from one side of the print and exiting on the opposite side
asphyxiation - petechiae on eyelids
formed when blood escapes tissues as capillaries burst - witnessed in both hangings and strangulation
How many different nucleotide bases are associated with the makeup of DNA?
four
The _____ amendment protects against unreasonable searches and seizures.
fourth
f
frequency of radiation
standard for admissibility of evidence
frye standard, daubert standard, rule 702
chlorate mixtures
fuel and a good oxidizing agent, potassium chlorate, when mixed with sugar produces a explosive mix
external examination
general body characteristics (height, weight, specific tattoos etc.) - photograph
A class characteristic:
involves association with a group
Which is a device used to screen objects for the presence of explosive residues?
ion-mobility spectrometry
weight
is the force with which gravity attracts a body.
neutron activation analysis is a good procedure for the analysis of activated _____.
isotopes
exit wound
lacerated type appearance
Admittance to the crime scene must include only:
law enforcement and forensic personnel assigned to the case.
testimonial evidence
lay witnesses and expert witnesses
All fingerprints are divided into 3 classes based on:
loops, whorls and arches
methods for impressions on soft earth
photography and casting class I dental stone (recommended) • allow to air dry 24-48 hours before shipped to lab • snow impression wax is also available
preservation of prints
photography, protect the print with cellophane if small but if big use powder + lifting, digital imaging for fingerprint enhancement
methods of crime scene recording
photography, sketches, notes, videos
silver nitrate based reagent formulated
physical developer of latent fingerprints on porous surfaces
basic services of a crime lab
physical science unit, biology unit, firearms unit, document examination unit, photography unit
whorl types
plain, central pocket loop, double loop, accidental
Light that is confined to a single plane of vibration is said to be _____.
plane polarized
non-biological evidence
plastic bag
Entomophilous plants
pollen carried and dispersed by insects or small animals
Anemophilous plants
pollen dispersed by wind
The technique for replicating or copying a portion of a DNA strand outside a living cell is called
polymerase chain reaction
basis for drug scheduling
potential for abuse, potential for physical and psychological dependence/addiction, and medical value/use
subpoena duces tecum
presence of the witness in court, but also any documentation or evidence in his or her possession that is material to the case
powder and superglue
prints on hard and nonabsorbent surfaces (glass, mirror, tile)
chemical
prints on soft and porous surfaces (paper, cardboard, cloth)
distribution
alcohol uniformly distributed throughout the watery portions of the body (2/3 body volume); fat, bones and hair low in water; maximum alcohol level in the blood
The collection of evidence from a tomb site by a forensic anthropologist must include:
all of the above
mass
refers to the amount of matter an object contains independent of gravity.
the bending of a light wave as it passes from one medium to another is referred to as
refraction
immersion is a method used by scientists to determine the _____ of a glass particle
refractive index
Two monocular compound microscopes properly spaced and aligned describe the _____ microscope.
stereomicroscope
intermediate
stippling with no soot
The appearance of an intermediate gunshot wound typically shows...
stippling with no soot.
firearm evidence - individual characteristics
striation marks
glass that is made stronger than ordinary window glass by introducing stress through rapid heating and cooling of the glass surface is called
tempered glass
chemistry of fire - ignition temperature
the minimum temperature at which a fuel spontaneously ignites
DNA
the molecules carrying the body's genetic information; DNA is double stranded in the shape of a double helix
An area within a deposited spatter pattern that is clear of spatter, caused by an object or person blocking the area at the time of the spatter's deposition is known as a _____.
void pattern
incoherent radiation
waves that are all out of step with each other.
physical properties of matter
weight, volume, color, boiling point, melting point
lacerations
tearing and splitting of the skin of the skin (bleeding)
DFO
a substitute for Ninhydrin; A chemical fingerprint developer (1,8-diazafluoren-9-one)
nucleus
the core of an atom, containing the protons and neutrons.
chop wound
"hybrid" type wound - blunt and sharp force trauma - sharp edges with underlying bone
Alphonse Bertillon
- the first scientific system of personal identification - 1879, began to develop the science of anthropometry, a systematic procedure of taking a series of body measurements as a means of distinguishing one individual from another - used for almost two decades, but replaced by fingerprinting in the early 1900s - known as the father of criminal identification
analysis of flammable residues:
- the headspace technique - vapor concentration
responsibilities of the first officer
- securing the crime scene so the lead investigator begins evaluating the area - obtain medical assistance for injured persons - make arrests if possible - isolate and protect the crime scene - exclude unauthorized persons - detain and separate witnesses - establish a perimeter - witnesses should not be allowed to communicate to avoid colluding
different scale patterns (coronal, imbricate and spinous)
(a) The coronal, or crownlike, scale pattern resembles a stack of paper cups. (b) Spinous or petal-like scales are triangular in shape and protrude from the hair shaft. (c) The imbricate, or flattened-scale, type consists of overlapping scales with narrow margins
fifth amendment
- self-incrimination - due process clause
drug dependence
- "habit-forming" - complex array of physiological and social factors - interaction with individual - societal aspects
Dr. Karl Landsteiner
- 1901, discovered that blood can be grouped into different categories (A, B, AB, and O)
Frye Standard
- 1923 - court must determine whether the questioned procedure, technique or principle is "generally accepted" by a meaningful segment of the relevant scientific community
Daubert Standard
- 1993 - trial judge acts as "gatekeeper" in determining the admissibility and reliability of scientific evidence presented in their courts
Which of the following is a sub classification of the whorl fingerprint patterns:
- Accidental whorl - Plain whorl - Central pocket loop whorl - Double loop whorl
analytical techniques used in paint comparison
- Characterization of Paint Binders: Pyrolisis: The decomposition of organic matter by heat IR spectrophotometry. - Characterization of Pigments: Emission Spectroscopy inductively coupled plasma (ICP) X-ray spectroscopy.
methods to document bloodstain pattern evidence
- Grid method: Involves setting up a grid of squares of known dimensions over the entire pattern using string and stakes - Perimeter rule method: Involves setting up a rectangular border of rulers around the pattern
chain of custody form
- serves to identify the evidence - verify that what is being presented in court is what was collected at the scene - identifies everyone that came into
Edmond Locard
- a Frenchman, demonstrated how the principles enunciated by Gross could be incorporated within a workable crime laboratory - formal education was in both medicine and law - 1910, he persuaded the Lyons police department to give him two attic rooms and two assistants to start a police laboratory - from modest beginnings, his research and accomplishments became known throughout the world - became the founder and director of the Institute of Criminalistics at the University of Lyons - believed that when a person comes in contact with an object or person, a cross-transfer of materials occurs - maintained that every criminal can be connected to a crime by dust particles carried from the crime scene, reinforced by a series of successful investigations - after World War I, his successes served as an impetus for the formation of police laboratories in Vienna, Berlin, Sweden, Finland, and Holland
Leone Lattes
- a professor at the Institute of Forensic Medicine at the University of Turin in Italy - 1915, he devised a relatively simple procedure for determining the blood group of a dried bloodstain, later applied to criminal investigations
blunt force trauma characteristics (recognize images)
- abrasions - contusions - lacerations
Arson investigators must work quickly to collect evidence at a fire scene because:
- accelerants in soil may rapidly degrade - safety requirements may require that clean up and salvage operations begin quickly - accelerant residues may quickly evaporate (all of the mentioned answers)
estimating time of death
- algor mortis - livor mortis - rigor mortis - potassium eye levels - stomach contents - decomposition
legal considerations at the crime scene
- anything removed must be in accordance with the 4th amendment - obtain a search warrant when time and circumstances permit - you can go on without a warrant when there is an: emergency circumstances, loss or destruction of evidence, if there is probable cause, consent of the involved parties
decomposition
- autolysis: self-digestion of cells in the body by enzymes - putrefaction: bacterial decomposition of the body
Walter C. McCrone
- became the world's preeminent microscopist - a tireless advocate for applying microscopy to analytical problems, particularly forensic science cases - responsible for educating thousands of forensic scientists throughout the world in the application of microscopic techniques - used microscopy, often in conjunction with other analytical methodologies, to examine evidence in thousands of cases
examples of low explosives
- black powder - safety fuse - smokeless powder (single base) - smokeless powder (double base) - chlorate mixtures - gas-air mixtures
collection and preservation of blood
- blood drawn under medically acceptable conditions (nonalcoholic disinfectant) - preserve sealed in an airtight container after adding an anticoagulant and a preservative (anticoagulant, a substance that prevents coagulation or clotting of blood (EDTA, potassium oxalate) and preservative, a substance that stops the growth of microorganisms in blood (sodium fluoride)) - affected by storage temperature, presence of a preservative and the length of storage (keep refrigerated) - postmortem blood samples; ethyl alcohol can be generated as a result of bacterial action; collect a number of blood samples from different body sites: femoral vein, heart and cubital vein
types of autopsy
- clinical/hospital autopsy: diagnose the disease that causes the death; focus on the internal organ findings and medical conditions, seeking to confirm clinical diagnoses, the presence and extent of disease, any medical conditions that were overlooked, and the appropriateness and outcome of therapy. - forensic/medicolegal autopsy: determine the cause of death and manner of death for legal/criminal purposes (external and internal analysis of the body); determine the cause of death and confirm the manner of death, often to be used in criminal proceedings and emphasizes external and internal findings while developing meaningful forensic correlations between sustained injuries and the crime scene
forensic analysis of soil
- color comparison - low-power microscopic examination - high-power microscopic examination - mineral: A naturally occurring crystalline solid. - comparison minerals and rocks. - many points of comparison
heat transfer
- conduction - convection - radiation
indications of an arson fire
- deliberate fire 1. the presence of an accelerant (accelerant, any material used to start or sustain a fire) 2. elimination of natural or accidental causes of a fire 3. fire trails 4. multiple points of origin
Calvin Goddard
- determine whether a particular gun has fired a bullet requires a comparison of the bullet with one that has been test-fired from the suspect's weapon - U.S. Army colonel, refined the techniques by using the comparison microscope - established the comparison microscope as the indispensable tool of the modern firearms examiner
Albert S. Osborn
- development of the fundamental principles of document examination was responsible for the acceptance of documents as scientific evidence by the courts - 1910, authored the first significant text in this field, "Questioned Documents", which is still considered a primary reference for document examiners
Mathieu Orfila
- father of forensic toxicology - became a renowned teacher of medicine in France - 1814, published the first scientific treatise on the detection of poisons and their effects on animals, establishing forensic toxicology as a legitimate scientific endeavor
collection and preservation of drug evidence
- field investigator is responsible for ensuring that the evidence is properly packaged and labeled for delivery to the lab - package must prevent the loss and/or cross-contamination - original container in which the drug was seized will suffice to meet these requirements - volatile solvents must be packaged in an airtight container - marked with sufficient information to ensure identification - investigator should supply any background information that may relate to a drug's identity - results of drug-screening tests used in the field must also be transmitted to the laboratory (not conclusive evidence of a drug ́s identity)
Francis Galton
- first definitive study of fingerprints and developed a methodology of classifying them for filing - 1892, he published a book titled Finger Prints, which contained the first statistical proof supporting the uniqueness of his method of personal identification - work described the basic principles that form the present system of identification by fingerprints
medium velocity (physical description and images)
- force of 5-25 ft/sec applied - typically produces bloodstains between 1mm - 3mm in diameter. - common in cases of blunt force (beating) or sharp force (cutting/stabbing) trauma
low-velocity spatter (physical description and images)
- force of <5 ft /sec applied - typically produces bloodstains >3 mm in diameter - normally produced by gravity alone, by a minimal force, or by an object dropping into and splashing blood from a blood pool
high-velocity spatter (physical description and images)
- force of >100 ft/sec applied - typically produces bloodstains <1 mm in diameter - common in gunshot exit wounds or explosions
analysis of blood for alcohol
- gas chromatography - enzyme alcohol dehydrogenase and coenzyme NAD (spectrophotometer (hospitals))
gunshot wounds (recognize images)
- hard contact - loose contact - close
types of explosives
- high and low explosives - deflagration and detonation
manner of death
- homicide - suicide - accidental - natural causes - undetermined
significance of physical evidence
- identification - comparison - individual characteristics - class characteristics - odds of finding class evidence is significantly greater - assigning probability values to class evidence is difficult - several types of class evidence together can however be significant - are statistical databases available to calculate probability rates for evidence? - are findings by forensic scientists subjective?
sharp force trauma characteristics (recognize images)
- incised wound - stab wound - chop wound
searching the fire scene:
- indications of an arson fire - timeliness of investigation - locating the point of origin - searching for accelerants
gunshot wounds - characteristics of varying distances
- intermediate - distant - exit wound
different types of examinations during the autopsy process
- internal examination - external examination - toxicology report
spiral search pattern
- inward spiral method is helpful because the searcher is moving from an area light with evidence to an area where more evidence will most likely be found - with either spiral approach the searcher can easily locate footprints leading away from the scene in any direction - completing a perfect spiral is often difficult, and evidence could be missed
four general classification of drugs
- narcotics - hallucinogens - depressants - stimulants
sex determination from skeletal bones (recognize images)
- pelvis - skull - mandible (jaw)
examples of high explosives
- primary explosive - secondary explosive
fourth amendment
- prohibits unreasonable searches and seizures - search warrant should be obtained,
drug dependence: interaction with the individual
- psychological dependence - physical dependence
types of evidence
- real evidence - testimonial evidence
functions of a forensic scientist
- scientific analysis of physical evidence - offering of expert testimony in cases - furnish training in the proper recognition, collection, and preservation of evidence
forensic drug analysis
- screening color tests (five primary color test reagents and the drug that each reagent tests for) - microcrystalline tests - confirmatory tests
age determination from skeletal bones (recognize images)
- sections of skull fuse at different stages in early development - fusion or lack of fusion can estimate age of infant - teeth formation also used for estimating age of infants - fusion of jaw, fingers, wrist, long bones and clavicle useful - pubic symphysis slowly changes over time from ridged to smooth
role of forensic toxicologist
- toxicologists detect and identify drugs and poisons in body fluids, tissues, and organs - crime labs and medical examiners ́ offices - hospital laboratories and health facilities to monitor intake of drugs and other toxic substances - violations of criminal law - depending on the state, responsibilities lie on crime labs, medical examiner or share by both - ethyl alcohol most heavily abused drug in Western countries =- after detected, identified and quantitated a drug or poison, assess the substance ́s toxicity; tolerance based on medical history.
Han Gross
- wrote the first treatise describing the application of scientific disciplines to the field of criminal investigation in 1893 - a public prosecutor and judge in Austria, he spent many years developing principles of criminal investigation. - his classic book Handbuch für Untersuchungsrichter als System der Kriminalistik (aka Criminal Investigation), he detailed the assistance that investigators could expect from the fields of science (microscopy, chemistry, physics, mineralogy, zoology, botany, anthropometry, and fingerprinting) - later introduced the forensic journal Archiv für Kriminal Anthropologie und Kriminalistik, which still is used for reporting improved methods of scientific crime detection
glass fractures and the 3R rule
-Fragments are assembled and physically fitted together -PROBLEM: GLASS EVIDENCE TOO FRAGMENTARY OR TOO MINUTE TO PERMIT A COMPARISON -DENSITY AND REFRACTIVE INDEX ARE MOST WIDELY USED FOR CHARACTERIZING GLASS PARTICLES - GRIM (Glass Refractive Index Measurement) 3 - Radial Fracture. A crack in a glass that extends outward like the spoke of a wheel from the point at which the glass was stuck. -Concentric Fracture. A crack in a glass that forms a rough circle around the point of impact. - 3R rule:Radial cracks form a Right angle on the Reverse side of the force -A fracture always terminates at an existing line of fracture.
The elimination or burn off rate of alcohol averages _____ percent w/v per hour.
.015
blood alcohol laws in the US
0.08% US for regular divers and 0.04% for commercial drivers - 0.01 to 0.05 subclinical - 0.03 to 0.12 euphoria - 0.09 to 0.25 excitement - 0.18 to 0.30 confusion - 0.25 to 0.40 stupor - 0.35 to 0.50 coma - 0.45 or more death
secure the scene
1
parts of the compound microscope - eyepiece or ocular lens
10. This is the lens closest to the eye. A microscope with only one eyepiece is monocular; one constructed with two eyepieces (one for each eye) is binocular
fundamental principles of fingerprints
1. A finger print is an individual characteristic, no two fingerprints have yet been found to possess identical ridge characteristics 2. A fingerprint will remain unchanged during an individual's lifetime. 3. Fingerprints have general ridge patterns that permit them to be systematically classified.
timeliness of investigation
1. any accelerant residues that remain after a fire is extinguished may evaporate within a few days or hours 2. begin an immediate investigation
locating the point of origin
1. low burning 2. v-patterns 3. wood charring 4. spalling of plaster or concrete (spalling is the destruction of a surface due to heat or other factors 5. material distortion 6. soot and smoke staining
7 S's of a crime scene
1. secure the scene 2. separate the witnesses 3. scan the scene 4. see the scene 5. sketch the scene 6. search for evidence 7. secure and collect evidence
general information provided by blood spatter
1. the direction from which blood originated 2. the angle at which a blood droplet struck a surface 3. the location or position of a victim at the time a bloody wound was inflicted 4. the movement of a bleeding individual at the crime scene 5. the minimum number of blows that struck a bleeding victim 6. the approximate location of an individual delivering blows that produced a bloodstain pattern
parts of the compound microscope - base
1. the support on which the instrument rests
separate the witnesses
2
parts of the compound microscope - arm
2. A C-shaped upright structure, hinged to the base, that supports the microscope and acts as a handle for carrying.
An eyepiece lens of 10x used in combination with an objective lens of 20x has a total magnification power of _____.
200X
The ratio of alcohol in the blood to alcohol in alveoli air is approximately.
2100:1
scan the scene
3
The temperature at which the breath leaves the mouth is normally...
34 degrees celsius.
see the scene
4
ACE-V
4 steps (analysis, comparison, evaluation, and verification)
parts of the compound microscope - body tube
4. A cylindrical hollow tube on which the objective and eyepiece lenses are mounted at opposite ends. This tube merely serves as a corridor through which light passes from one lens to another.
sketch the scene
5
parts of the compound microscope - coarse adjustment
5. This knob focuses the microscope lenses on the specimen by raising and lowering the body tube.
search for evidence
6
parts of the compound microscope - fine adjustment
6. The movements effected by this knob are similar to those of the coarse adjustment but are of a much smaller magnitude.
secure and collect evidence
7
parts of the compound microscope - illuminator
7. Most modern microscopes use artificial light supplied by a lightbulb to illumi- nate the specimen being examined. If the specimen is transparent, the light is directed up toward and through the specimen stage from an illuminator built into the base of the micro- scope. This is known as transmitted illumination. When the object is opaque—that is, not transparent—the light source must be placed above the specimen so that it can reflect off the specimen's surface and into the lens system of the microscope. This type of illumination is known as vertical or reflected illumination.
parts of the compound microscope - condenser
8. collects light rays from the base illuminator and concentrates them on the specimen. The simplest condenser is known as the Abbé condenser. It consists of two lenses held together in a metal mount. The condenser also includes an iris diaphragm that can be opened or closed to control the amount of light passing into the condenser.
serum
the liquid that separates from the blood when a clot is formed
parts of the compound microscope - objective lens
9. this is the lens positioned closest to the specimen. To facilitate changing from one objective lens to another, several objectives are mounted on a revolving nosepiece or turret located above the specimen. Most microscopes are parfocal, meaning that when the microscope is focused with one objective in position, the other objective can be rotated into place by revolving the nosepiece while the specimen remains very nearly in correct focus.
The role of the crime scene investigation team at a crime usually begins with?
Documenting and photographing the scene
arterial spurt spatter patterns
A characteristic bloodstain pattern containing spurts that resulted from blood exiting under pressure from an arterial injury
ninhydrin
A chemical reagent used to develop latent fingerprints on porous materials by reacting with amino acids in perspiration
Paul Kirk
A biochemist, educator, and criminalist; wrote Criminal Investigation in 1953; helped to develop the careers of many criminalists; developed the first academic program in criminalistics
transfer patterns
A bloodstain pattern created when a surface that carries wet blood comes in contact with a second surface; recognizable imprints of all or a portion of the original surface or the direction of movement may be observed; object with blood comes in contact with another object without blood; blood surfaces leaves an imprint on surface
cast off spatter patterns
A bloodstain pattern that is created when blood is flung from a blood-bearing object in motion onto a surface.
homozygous alleles on a DNA profile
A gene pair made of two similar genes Example: 12,12 (at some STR)
macromolecule
A molecule with a high molecular mass.
expirated spatter patterns
A pattern created by blood that is expelled out of the nose, mouth, or respiratory system as a result of air pressure and/or airflow.
STRs
A region of a DNA molecule that contains short segments consisting of three to seven repeating base pairs.
tandem repeats
A region of a chromosome that contains multiple copies of a core DNA sequence that are arranged in a repeating fashion (e.g., Restriction fragment length polymorphisms (RFLPs) & Short Tandem Repeats (STRs). • Act as filler or spacers between the coding regions of DNA. • Offers a means of distinguishing one individual from another through DNA typing
chromosome
A rodlike structure in the cell nucleus, along which the genes are located; it is composed of DNA surrounded by other material, mainly proteins.
polymer
A substance composed of a large number of atoms; these atoms are usually arranged in repeating units or monomers.
superglue fuming
A technique for visualizing latent fingerprints on nonporous surfaces by exposing them to cyanoacrylate vapors; named for the commercial product Super Glue.
follicular tag
A translucent piece of tissue surrounding the hair ́s shaft near the root; it contains the richest source of DNA associated with hair.
gene
A unit of inheritance consisting of a DNA segment located on a chromosome.
all possible blood types
A+, A-, B+, B-, AB+, AB-, O+, O-
The _____ is a system for classifying blood according to general groups or types.
A-B-O system
DNA coding
A-T G-C
various tests for seminal stains
Acid phosphatase: an enzyme found in high concentration in semen; microscopic examination of semen; Prostate Specific Antigen (PSA) by electrophoresis
Which of the following drugs is a depressant?
Alcohol
How is alcohol introduced in the lungs breath?
Alcohol travels through the bloodstream and is transferred into the alveolus sac.
Who developed the first forensic DNA typing method, "DNA fingerprinting"?
Alec Jeffries
Major contributors to forensic science include
Alphonse Bertillion and Walter McCrone
ALS
Alternative Light Source on porous material
void spatter patterns
An area within a deposited spatter pattern that is clear of spatter, caused by an object or person blocking the area at the time of the spatter's deposition.
isotope
An atom differing from another atom of the same element in the number of neutrons in its nucleus.
different phases of hair growth and what takes place during each phase
Anagen Phase. The initial growth phase during which the hair follicle actively produces hair. Catagen Phase. A transition stage between the anagen and telogen phases of hair growth. Telogen Phase. The final growth phase in which hair naturally falls out of the skin
What are the functions of a forensic scientist?
Analyze physical evidence, report findings, serve as expert witness
gel diffusion and how it works
Another version of the precipitin test, called gel diffusion, takes advantage of the fact that anti- bodies and antigens diffuse or move toward one another on a plate coated with a gel medium made from a natural polymer called agar. The extracted bloodstain and the human antiserum are placed in separate holes opposite each other on the gel. If the blood is of human origin, a line of precipitation will form where the antigens and antibodies meet. Similarly, the antigens and antibodies can be induced to move toward one another under the influence of an electrical field. In the electrophoretic method, an electrical potential is applied to the gel medium; a specific antigen-antibody reaction is denoted by a line of precipitation formed between the hole containing the blood extract and the hole containing the human antiserum. The precipitin test is very sensitive and requires only a small amount of blood for testing. Human bloodstains dried for 10 to 15 years and longer may still give a positive precipitin reaction. Even extracts of tissue from mummies four to five thousand years old have given positive reactions with this test. Furthermore, human bloodstains diluted by washing in water and left with only a faint color may still yield a positive precipitin reaction. Once it has been determined that the bloodstain is of human origin, an effort must be made to associate or disassociate the stain with a particular individual. Until the mid-1990s, routine characterization of bloodstains included the determination of A-B-O types; however, the widespread use of DNA profiling or typing has relegated this subject to one of historical interest only.
The first systematic attempt at personal identification (Bertillon System) was known as
Anthropometry
allele
Any of several alternative forms of a gene located at the same point on a particular pair of chromosomes; for example, the genes determining the blood types A and b are alleles.
AFIS
Automated Fingerprint Identification System scans fingerprints electronically and plots the positions of their ridge characteristics, comparing them with prints in a database; Once the quality of the print has been deemed suitable for the NGI system search, the latent-print examiner creates a digital image of the print with either a digital camera or a scanner. Next, the examiner, with the aid of a coder, marks points on the print to guide the computerized search. The print is then elec- tronically submitted to the NGI system, and within minutes the search is completed against all fingerprint images in the NGI system; the examiner may receive a list of potential candidates and their corresponding fingerprints for comparison and verification
Type B blood contains _____ antigens.
B
non-coding DNA
Does not encode for proteins. Often contains sequences that are repeated numerous times (e.g., Tandem repeats). (~30% of the genome)
antigens/antibodies in each type of blood
Blood A - A/ANTI-B Blood B - B/ANTI-A Blood AB - A,B/NONE Blood O - NONE/ANTI-A, ANTI-B
While testing anti-A serum on a whole blood sample agglutination was observed, and the Rh factor test was positive. What is the blood type for the sample?
Blood type could be either be A+ or AB+
drip patterns
Bloodstain pattern resulting from blood dripping into blood
...refers to injury to the body from a non-sharp or broad object.
Blunt-force trauma
molecule
smallest unit of a compound.
searching for accelerants
sniffer and sniffer dog
When dealing with physical evidence, if a suspect sample is not available for comparison then you cannot proceed with the forensic investigation.
False
Which of the following drugs is a stimulant?
Cocaine
_____ is the process and a document that memorializes the transfer of evidence from one person to another.
Chain of custody
CODIS stands for
Combined DNA Index System
newer chemical processes
DFO, Dye combos known as RAM, RAY, MRM 10, and superglue fuming, porous materials + ALS
The process of isolating and reading DNA markers is referred to as
DNA fingerprinting, DNA typing, and DNA profiling (all of the mentioned answers).
structure of DNA
DNA is like a ladder or spiral staircase. The outside is made of a sugar-phosphate backbone with alternating sugars and phosphates and the inside "steps" are the nitrogenous bases; double helix
nuclear DNA
DNA present within the nucleus of a cell; this form of DNA is inherited from both parents.
_____ is a testimony given under oath but not in court or before a judge.
Deposition
RFLPs
Different fragment lengths of base pairs that result from cutting a DNA molecule with restriction enzymes.
_____ is the process where one side in litigation seeks to gather information about testimony and evidence that is in the hands of the other side.
Discovery
Who stated every contact leaves a trace?
Edmond Locard
chain of custody
Evidence labeling - What it is - Where it is was collected from - Who collected it - Time and date of collection - Evidence number - Case number
The _____ Laboratory is now the world's largest forensic laboratory.
FBI
fact vs expert witness
Fact witness: person who testifies as to what s/he has seen, heard, or otherwise observed regarding a circumstance, event or occurrence as it actually took place. Generally not allowed to offer opinion. Expert witness: person who by reason of education or specialized experience possesses superior knowledge respecting a subject about which persons having no particular training are incapable of forming an accurate opinion.
Under the controlled substances act, drugs are divided into how many different schedules?
Five
method for comparing density and the principle behind this method
Flotation Method. Based on standard/reference glass particle is immersed in a liquid; a mixture of bromoform and bromobenzene. Suspended in the liquid, equal densities Sink or float, more or less densities Density no homogeneous. Differ as much as 0.0003 g/ml. Flotation Method distinguish glass particles that differ in density by 0.001 g/m
color test for blood
For many years, the most commonly used test was the benzidine color test; however, because benzidine has been identified as a known carcinogen, its use has generally been discontinued, and the chemical phenolphthalein is usually substituted in its place (this test is also known as the Kastle-Meyer color test). Both the are based on the observation that blood hemoglobin possesses peroxidase-like activity. Peroxidases are enzymes that accelerate the oxidation of several classes of organic compounds by peroxides. When a bloodstain, phenolphthalein reagent, and hydrogen peroxide are mixed together, the blood's hemoglobin causes the formation of a deep pink color. The Kastle-Meyer test is not a specific test for blood; some vegetable materials, for instance, may turn Kastle-Meyer pink. These substances include potatoes and horseradish. However, it is unlikely that such materials will be encountered in criminal situations, and thus from a practical point of view, a positive Kastle-Meyer test is highly indicative of blood. Field investigators have found Hemastix strips a useful presumptive field test for blood. Designed as a urine dipstick test for blood, the strip can be moistened with distilled water and placed in contact with a suspect bloodstain. The appearance of a green color is indicative of blood.
tempered glass
Glass that is strengthened by introducing stress through rapid heating and cooling of the glass surfaces.
Frye vs Daubert
Frye: the results of scientific tests or procedures are admissible as evidence only when the tests or procedures have gained general acceptance in the particular field to which they belong Daubert: the standard used by a trial judge to assess whether an expert witness's scientific testimony is based on scientifically valid reasoning which can properly be applied to the facts at issue; judge is 'gatekeeper'
A confirmatory test for drug analysis is:
GC-MS
float glass
Glass is manufactured by melting sand and other desired ingredients and then allowing the mixture to cool without crystallizing. The colling process may take place in a mold or it may be injected into a particular shape or it may be cooled in such a way that is perfectly flat.
heterozygous
Having two different allelic genes on two corresponding positions of a pair chromosomes
homozygous
Having two identical allelic genes on two corresponding positions of a pair of chromosomes.
method for comparing refractive index and the principle behind this method
Immersion Method. Glass particles are immersed in a liquid medium whose refractive index is adjusted until it equals that of the glass particles. Match point, disappearance of the Becke Line and minimum contrast between the glass and liquid medium. Becke line. A bright halo that is observed near the border of a particle immersed in a liquid of a different refractive index.
What type of image cannot be viewed directly?
virtual image
AFIS
In the United States, each state has its own automated fingerprint identification system, linked to the FBI's NGI system.
IAFIS
Integrated Automated Fingerprint Identification System, a national fingerprint and criminal history system maintained by the FBI.
A fingerprint left by someone with soiled or stained fingers is called a:
visible print
Which of the following drugs is a hallucinogen?
LSD
LR
Likelihood Ratio - Amount of people you would have to test before getting a random match • LR=1/RMP • Makes a "match" more powerful
What is the oldest Forensic Laboratory in the United States?
Los Angeles Police Department
The oldest forensic laboratory in the United States is that of the _____, created in 1923 by _____, a police chief from Berkeley, California.
Los Angeles Police Department; August Vollmer
_____ reagent reacts with blood causing it to luminesce.
Luminol
mtDNA
Mitochondrial DNA; DNA present in small structures (mitochondria) outside the nucleus of a cell; mitochondria supply energy to the cell; this form of DNA is inherited maternally (from the mother). •mtDNA maternally inherited •Cell contains one nucleus vs hundreds-thousands of mitochondria • More mtDNA available • When nuclear DNA is degraded or limited, mtDNA may still be present. (great for forensic analysis) •mtDNA analysis more expensive
ulnar loop
Name this fingerprint: one delta, loop opens to the pinky
radial loop
Name this fingerprint: one delta, loop opens towards the thumb
The drugs morphine, heroin, methadone, and codeine belong to which category of drug?
Narcotics
NIBIN
National Integrated Ballistics Information Network allows firearms analysts to acquire, digitize, and compare markings made by a firearm on bullets and cartridge casings recovered from crime scenes - introduced by the FBI & ATF (Bureau of Alcohol, Tobacco, & Firearms) - automated search system for local, state and federal labs - useful screening tool but still requires an examiner
NAMUS
National Missing and Unidentified Persons System - Available to medical examiners office, law enforcement and general public
Is it ok to search a crime scene immediately if you clearly see a dead body and know a crime has been committed?
No
A type AB mother and type AB father will have offspring of the following possible phenotypes except:
O
precipitin test and how it works
Once the stain has been characterized as blood, the serologist determines whether the stain is of human or animal origin. For this purpose, the standard test used is the precipitin test. Precipitin tests are based on the fact that when animals (usually rabbits) are injected with human blood, antibodies form that react with the invading human blood to neutralize its presence. The investi- gator can recover these antibodies by bleeding the animal and isolating the blood serum. This serum contains antibodies that specifically react with human antigens. For this reason, the serum is known as human antiserum. In the same manner, by injecting rabbits with the blood of other known animals, virtually any kind of animal antiserum can be produced. Currently, antiserums are commercially available for humans and for a variety of commonly encountered animals—for example, dogs, cats, and deer. A number of techniques have been devised for performing precipitin tests on bloodstains. The classic method is to layer an extract of the bloodstain on top of the human antiserum in a capillary tube. Human blood, or for that matter, any protein of human origin in the extract, reacts specifically with antibodies present in the antiserum, as indicated by the formation of a cloudy ring or band at the interface of the two liquid; An antibody that reacts with its corresponding antigen to form a precipitate.
a computerized database that allows an analyst to obtain information relating to an automobile's make, model, and year is:
PDQ
PDQ
Paint Data Query - Chemical and color information from original automotive paints - Developed and maintained by Royal Canadian Mounted Police (RCMP), - 40 U.S forensic laboratories and police agencies in 21 different countries
What are the basic services provided by Full-Service Crime Laboratory?
Physical Science Unit, Biology Unit, Firearms Unit, Photography Unit, Document Examination Unit
h
Planck's constant
protein
Polymers of amino acids that play basic roles in the structures and functions of living things. Protein control inheritable traits; Proteins are made by linking a combination of amino acids; DNA directs the production of complex molecules called proteins; The genetic information that determines the amino acid sequence for every protein manufactured in the human body is stored in DNA in a genetic code
the computer software for comparing shoe prints is known as _____.
SICAR
methods for analyzing trace elements
Presence of "trace elements" is particularly useful because they provide "invisible" markers that may establish the source of a material or at least provide additional points for comparison. Source of origin Combine elemental analysis with refractive index
Short DNA segments containing repeating sequences of three to seven bases are called _____.
STR
SICAR
Shoeprints Image Capture and Retrieval - Not government controlled - Commercially available - Database (solemate) containing over 35,000 entries - Similar database (Treadmate) database for tire tread patterns
RMP
Random Match Probability - How frequently the DNA profile occurs in population • Use the product rule • Product of all the frequencies at N loci MP (freq of profile) = (freq locus1)*(freqlocus2)*(freq locus3)*(freq locusN) • After calculating frequency at each loci, multiple all of them together to get MP
RUVIS
Reflected Ultraviolet Imaging System; a device that can locate prints on most nonabsorbent surfaces without the aid of chemical or powder treatments with an ultraviolet image converter for the purpose of detecting latent fingerprints
Which of the following color test can be performed for the identification of cocaine?
Scott
Which is NOT a manner of death?
Sharp-force trauma
satellite spatter
Small drops of blood that are distributed around the perimeter of a drop or drops of blood and were produced as a result of the blood impacting the target surface.
mitochondria
Small structures located outside the nucleus of a cell; these struc- tures supply energy to the cell; maternally inherited DNA is found in each mitochondrion.
Which of the following is considered to be an acceptable crime scene search pattern?
Spiral Search, Grid Search, Lineal Search
area of convergence
The area on a two-dimensional plane where lines traced through the long axis of several individual bloodstains meet
NIST
The National Institute for Standards and Technology
microcrystalline tests and how they work
The identification of blood can be made more specific if microcrystalline tests are performed on the material. Several tests are available; the two most popular ones are the Takayama and Teich- mann tests. Both of these depend on the addition of specific chemicals to the blood so that char- acteristic crystals with hemoglobin derivatives will form. Crystal tests are far less sensitive than color tests for blood identification and are more susceptible to interference from contaminants that may be present in the stain.
area of origin
The location in three-dimensional space from which blood that produced a bloodstain originated; the location of the area of convergence and the angle of impact for each bloodstain is used to approximate this area
genotype
The particular combination of genes present in the cells of an individual.
locus
The physical location of a gene on a chromosome.
phenotype
The physical manifestation of a genetic trait such as shape, color, and blood type.
DNA replication
The process in which DNA makes a duplicate copy of itself.
area of convergence calculated
This can be established by drawing straight lines through the long axis of several individual bloodstains, following the line of their tails. The intersection of these lines is the area of convergence, and the approximate point of origin will be on a line straight out from this area.
The FBI's Forensic Science Research and Training Center, opened in 1981, gave the United States a facility dedicated to conducting research to develop new and reliable scientific methods that can be applied to forensic science.
True
Vollmer headed the first U.S. university institute for criminology and criminal-istics at the University of California at Berkeley, but the official status wasn't established until 1948, when a school of criminology was formed.
True
In 1932, the FBI, under J. Edgar Hoover, organized a national laboratory that offered forensic services to all law enforcement agencies in the country.
True.
molecule
Two or more atoms held together by chemical bonds.
laminated glass
Two sheets of ordinary glass bonded together with a layer of plastic.
light amplification by stimulated emission of radiation produces light that has all its waves pulsating in unison. what is this?
a laser.
autopsy
a surgical procedure performed by a pathologist on a dead body to ascertain—from the body, organs, and bodily fluids—the cause of death
depressants
a substance that depresses the functions of the central nervous system; depressants calm irritability and anxiety and may induce sleep - ex: alcohol, barbiturates, antipsychotics, anti anxiety drugs, huffing
hallucinogens
a substance that induces changes in mood, attitude, thought processes, and perceptions - ex: marijuana, LSD, PCP (phencyclidine), mescaline, psilocybin, synthetic cannabis
antigen
a substance, usually a protein that stimulates the body to produce antibodies against it
flow patterns
a bloodstain pattern formed by the movement of small or large amounts of blood as a result of gravity's pull
periodic table
a chart of elements arranged in a systematic fashion; vertical rows are called groups or families, and horizontal rows are called series; elements in a given row have similar properties.
physical state
a condition or stage in the form of matter; a solid, liquid, or gas.
safety fuse
a cord containing a core of black powder, used to carry a flame at a uniform rate to an explosive charge
birefringence
a difference in the two indices of refraction exhibited by most crystalline materials.
latent fingerprint
a fingerprint made by the deposit of oils and/or perspiration; it is invisible to the naked eye
chemistry of fire - spontaneous combustion
a fire caused by a natural heat- producing process in the presence of sufficient air and fuel
element
a fundamental particle of matter; an element cannot be broken down into simpler substances by chemical means.
primary explosive
a high explosive that is easily detonated by heat, shock, or friction. Provide the major ingredients of blasting caps. Include lead azida, lead styphnate and diazodinitrophenol
secondary explosive
a high explosive that is relatively insensitive to heat, shock, or friction; high explosives for commercial and military blasting; dynamite, TNT (trinitroluene), PETN (pentaerythritol tetranitrate), RDX (cyclotrimethylenetrinitramine) and tetryl(2,4,6- trinitrophenylmethylnitramine)
schedule II
a high potential for abuse, a currently accepted medical use or a medical use with severe restrictions, and a potential for severe psychological or physical dependence; include opium and its derivatives not listed in schedule I, cocaine, methadone, PCP, most amphetamine preparations, and most barbiturate preparations containing amobarbital, secobarbital, and pentobarbital; dronabinol, the synthetic equivalent of the active ingredient in marijuana, has been placed in recognition of its growing medical uses in treating glaucoma and chemotherapy patients.
gamma ray
a high-energy form of electromagnetic radiation emitted by a radioactive element
x-ray
a high-energy, short-wavelength form of electromagnetic radiation.
schedule IV
a low potential for abuse relative to schedule III drugs and have a current medical use in the United States; their abuse may lead to limited dependence relative to schedule III drugs; Drugs controlled in this schedule include propoxyphene (Darvon), phenobarbital, and tranquilizers such as meprobamate (Miltown), diazepam (Valium), and chlordiazepoxide (Librium).
A-B-O system
a means of classifying blood by the antigens located on the surface of the red blood cells and the antibodies circulating in the plasma
livor mortis
a medical condition that occurs after death and results in the settling of blood in areas of the body closest to the ground - begins 20 mins - 3 hrs after death - may indicate time of death - affected by environmental conditions - determine if body was moved
mineral
a natural occurring crystalline solid
electron
a negatively charged particle that is one of the fundamental structural units of the atom.
neutron
a particle with no electrical charge that is one of the basic structures in the nucleus of an atom.
sublimation
a physical change from the solid state directly into the gaseous state.
density
a physical property of matter that is equivalent to the mass per unit volume of a substance.
proton
a positively charged particle that is one of the basic structures in the nucleus of an atom.
Every individual who enters a crime scene is?
a potential destroyer of physical evidence
voir dire
a preliminary examination of a witness or a juror by a judge or counsel
algor mortis
a process that occurs after death in which the body temperature continually cools until it reaches the ambient or room temperature - at average ambient temperatures of 70-72°F, the body loses heat at a rate of approximately of 1-1.5°F per hour until the body reaches the ambient or room temperature - affected by temperature, clothing and size of victim
scientific method
a process that uses strict guidelines to ensure careful and systematic collection, organization, and analysis of information
digital imaging for fingerprint enhancement
a process through which a picture is converted into a series of square electronic dots known as pixels; the picture is manipulated by computer software that changes the numerical value of each pixel
intensive property
a property that is not dependent on the size of an object.
antibody
a protein that destroys or inactivates a specific antigen; antibodies are found in the blood serum
compound
a pure substance composed of two or more elements.
hemoglobin
a red blood cell protein that trans-ports oxygen in the bloodstream; it is responsible for the red color of blood
confirmatory tests
a single test that specifically identifies a substance
photon
a small packet of electromagnetic radiation energy; each photon contains a unit of energy equal to the product of Planck ́s constant and the frequency of radiation.
liquid
a state of matter in which molecules are in contact with one another but are not rigidly held in place.
gas (vapor)
a state of matter in which the attractive forces between molecules are small enough to permit them to move with complete freedom.
solid
a state of matter in which the molecules are held closely together in a rigid state.
stimulants
a substance taken to increase alertness or activity - ex: amphetamines, cocaine
polymerase chain reaction (PCR)
a technique for replicating or copying a portion of a DNA strand outside a living cell; this technique leads to millions of copies of DNA strand; a technique for replicating or copying a portion of a DNA strand outside a living cell; this technique leads to millions of copies of the DNA strand.
iodine fuming
a technique for visualizing latent fingerprints by exposing them to iodine vapors
screening color tests
a test that is nonspecific and preliminary in nature
continuous spectrum
a type of emission spectrum showing a continuous band of colors all blending into one another.
line spectrum
a type of emission spectrum showing a series of lines separated by black areas; each line represents a definite wavelength or frequency.
beta particle
a type of radiation emitted by a radioactive element; the radiation consists of electrons.
alpha particle
a type of radiation emitted by a radioactive element; the radiation is composed of helium atoms minus their orbiting electrons
phase
a uniform body of matter; different phases are separated by definite visible boundaries.
deflagration
a very rapid oxidation reaction accompanied by the generation of a low-intensity pressure wave that can disrupt the surroundings
Which technique is used to extract explosive compounds from debris?
acetone wash
Satellite blood spatter around parent stains will have the pointed end facing _____.
against the direction of travel
The stage of fusion of various bones within a skeleton can be used to estimate the _____ of the decedent.
age
what cannot be determined from a hair sample
age and sex of an individual be determined from a hair sample (only infant hair and sex by nuclear DNA) DNA individualizes a human hair?- combination of microscopy + nuclear/mtDNA mtDNA cannot distinguish similar hairs from different individuals maternally related.
matter
all things of substance; matter is composed of atoms or molecules.
a type of radiation composed of a helium atom minus its electrons?
alpha
narcotics
an analgesic or painkilling substance that depresses vital body functions such as blood pressure, pulse rate, and breathing rate; regular administration of narcotics produces physical dependence - ex: opiates (morphine, heroin, codeine), synthetic opiates (oxycontin, methadone)
smokeless powder (double base)
an explosive consisting of a mixture of nitroglycerin and nitrocellulose
smokeless powder (single base)
an explosive consisting of nitrated cotton or nitrocellulose
high explosives
an explosive with a velocity of detonation greater than 1,000 meters per second
low explosives
an explosive with a velocity of detonation less than 1,000 meters per second
detonation
an extremely rapid oxidation reaction accompanied by a violent disruptive effect and an intense, high-speed shock wave
real image
an image formed by the actual convergence of light rays on a screen
virtual image
an image that cannot be seen directly; it can be seen only by a viewer looking through a lens
fingerprint
an impression left on any surface that consists of patterns made by the ridges on a finger
suicide
an individual taking his or her own life with lethal intention
expert witness
an individual whom the court determines to possess knowledge relevant to the trial that is not expected of the average layperson
applications of the Microspectrophotometer
an instrument that links a microscope to a spectrophotometer. spectrophotometry: quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. UV, visible and IR regions. Absorption Spectrum. Investigates counterfeit and authentic currency, fibers and paints. Fingerprint IR spectrum.
subpoena
an order issued under the direction of a court commanding the presence of a witness at a specific time and place to give testimony or other evidence
ACE-V is an acronym for which four-step process?
analysis, comparison, evaluation, and verification
A drug-protein complex can be injected into an animal to form specific _____ for that drug.
antibodies
On the surface of red blood cells are chemical substances called _____ which impart blood type characteristics to the cells.
antigens
soil
any disintegrated material, natural and/or artificial, that lies on or near the earth ́s surface. examples: rocks, minerals, vegetation, animal matter, glass, paint chips, asphalt, brick fragments, cinders
physical evidence
any object that can establish that a crime has or has not been committed or can link a crime and its victim or its perpetrator
evidence
anything that will help prove or disprove a material fact
relationship between height and size of bloodstain
as the height increased, the diameter and size increases
class characteristics
associated only with a group and never with a single source (blood type, lands and grooves on bullets)
asphyxiation - natural death vs foul play
at a fire scene, carbon monoxide bind with hemoglobin restricting oxygen transport to the body - high levels of carbon monoxide result in death - was individual dead prior to fire? - carbon monoxide levels will not build up after death - inhalation of soot if alive during fire
central pocket loop
at least one ridge that makes a complete circuit
the smallest particle of an element that can exist and still retain its identity as that element is the?
atom
impressed action marks are formed on the _____.
back of the cartridge case
When are fingerprints formed?
before birth
Which is NOT a high explosive?
black powder
NIBIN is maintained by the ATF for the purpose of:
compare markings made by a firearm on bullets
common types of physical evidence
blood, semen, and saliva, documents, drugs, explosives, fibers, fingerprints, firearms and ammunition, glass, hair, impressions, organs and physiological fluids, paint, petroleum products, plastic bags, plastic, rubber and other polymers, powder residues, serial numbers, soil and minerals, tool marks, vehicle lights, wood, and other vegetative matter
pool patterns
bloodstain patterns created when blood is collected on a level and undisturbed surface; stationary over time
what can be determined from a hair sample
body area from which a hair originated be determined, ancestral origin of hair, hair was forcibly removed from the body, determine whether hair came from a deceased individual
internal examination
body dissected and organs removed
methods for testing for intoxication
breath testing - measures the alcohol concentration in the pulmonary artery by measuring its concentration in alveolar breath - more reflective of the concentration of alcohol reaching the brain - ex: breathalyzer, infrared light absorption device, fuel cell detectors (a detector in which chemical reactions produce electricity)
contusions
bruise caused by rupturing and crushing of small blood vessels; skin does not break (e.g., black eye)
loose contact
burning and searing around circular wound -soot on skin
the mass of an object is determined
by comparison to the known mass of standard objects.
F =
c/λ
warrantless search
can be justified in cases of: - The existence of emergency circumstances - The need to prevent the immediate loss or destruction of evidence - Search of a person and property within the immediate control of the person, provided it is made incident to a lawful arrest - A search made by consent of the parties involved
_____ are firearms designed to be fired while resting on shoulder.
long guns
chemical properties of matter
characteristics that can be observed when a substance interacts with another substance; ability to react; inability to react; usually hidden
arch fingerprint
characterized by ridge lines that enter the print from one side and flow out the other side; do not have type lines, deltas, or cores.
inorganic
chemical compound not based on C.
GC, HPLC, and TLC are all analysis techniques that separate molecules based on their ability to move (partition) between a stationary phase and a mobile phase. this separation technique is called
chromatography
Genes are positioned on threadlike bodies called _____.
chromosomes
the number of lands and grooves and approximate width and direction of twist are _____.
class characteristics
chemistry of fire - glowing combustion
combustion on the surface of a solid fuel in the absence of heat high enough to pyrolyze the fuel
comparison
compare the questioned print to the known print at three levels: Level 1, looks at the general ridge flow and pattern configuration; Level 2, locating and comparing ridge characteristics, or minutiae; Level 3, examination and location of ridge pores, breaks, creases, scars, and other permanent minutiae.
Which microscope will you use to compare two bullets?
comparison microscope
what is the logical first step in soil analysis?
comparison of dried soil sample for color and texture
composition of paint and the role of each component
composition of paint: pigments impart color and hiding to paint, usually mixtures of organic and inorganic compounds. Binder provides support medium for the pigments and additives and is a polymeric substance Electrocoat primer: The first layer applied to the steel body of a car is the electrocoat primer. The primer, consisting of epoxy-based resins, is electroplated onto the steel body of the automobile to provide corrosion resistance. The resulting coating is uniform in appearance and thickness. The color of these electrodeposition primers ranges from black to gray. Primer surfacer: Originally responsible for corrosion control, the surfacer usually follows the electrocoat layer and is applied before the basecoat. Primer surfacers are epoxy-modified polyesters or urethanes. The function of this layer is to completely smooth out and hide any seams or imperfections, because the colorcoat will be applied on this surface. This layer is highly pigmented. Color pigments are used to minimize color contrast between primer and topcoats. For example, a light gray primer may be used under pastel shades of a colored topcoat; a red oxide may be used under a dark-colored topcoat. Basecoat: The next layer of paint on a car. This layer provideds the color and aeshtetics of the finish and represents the "eye appeal" of the finished automobile. The integrity of this layer depends on its ability to resist weather, UV radiation, and acid rain. Clearcoat: An unpigmented clear coat is applied to improve gloss, durability, and appearance,. Most are acrylic based, but polyurethane clearcoats are increasing in popularity. These topcoats provide outstanding etch resistance and appearance.
psychological dependence
conditioned use of a drug caused by underlying emotional needs
The role of the Forensic Scientist includes all of the following except...
conducting investigations
gas-air mixtures
considerable quantity of natural gas escapes into a confined area and mixes with a sufficient amount of air, concentration limits
accidental loop whorl
contains two or more patterns or is a pattern not covered by other categories
coroner vs pathologist
coroner: - investigation of death - no special training - appointed individual - law enforcement or administrator - gather's vital information about the case pathologist: - investigation of death - trained physician - board certified to conduct autopsies and determine cause of death - works in public heath - testifying in court
the _____ contains the pigment granules that impart color to hair.
cortex
the most prevalent plant fiber is
cotton.
To determine the ancestry of skeletal remains forensic anthropologists analyze...
cranium.
Dr. Bill/Willam Bass
creator of the "Body Farm" (officially named the Anthropology Research Facility), the world's first laboratory for decomposition research; best known for his research on human osteology and human decomposition. He has also assisted federal, local, and non-U.S. authorities in the identification of human remains
the _____ is the scale structure covering the exterior of the hair.
cuticle
incised wound
cutting or slicing/slitting parallel to the skin - wound is wider than it is deep - less lethal - common with defensive wounds
as the distance from the firearm and target increases, the amount of gunshot residue deposited on the target _____.
decreases
schedule I
deemed to have a high potential for abuse, have no currently accepted medical use in the United States, and/or lack accepted safety for use in treatment under medical supervision. (heroin, marijuana, methaqualone, and LSD)
stomach contents
degree of digestion of food may give clues as to the time of death
flotation is a method used by scientists to determine the _____ of a particle of glass.
density
the physical property measured by the formula mass per unit volume is
density
potassium eye levels (potassium levels in the fluid of the eye (vitreous humor))
determine rate at which potassium enters vitreous humor after death
clinical/hospital autopsy
diagnose the disease that causes the death
caliber
diameter of the bore of a rifled firearm
the term caliber refers to the
diameter of the bore of a rifled firearm
Watson and Crick demonstrated that DNA is composed of two strands coiled into the shape of a _____.
double helix
organic substances examples
drugs, accelerants, fibers, explosives, paint binders
E
energy of the photon
radiation
energy that is radiated or transmitted in the form of rays or waves or particles
gunshot wounds - entrance vs exit
entrance wounds: - circular ring like pattern - typically, smaller with a more regular pattern - soot/ stippling present depending on the distance exit wounds - lacerated type appearance - typically, larger and irregular - lack soot or stippling
What is the definition of "Pollen rain"?
estimation of the production and dispersal patterns of spores and pollen
an emission spectrograph vaporizes samples and heats them to a high temperature to produce an _____ state in which they emit light.
excited state
A witness that is allowed to express his/her opinion on a case is a _____.
expert witness
A(n) _____ is a person who can demonstrate a particular skill or has knowledge in a trade or profession that will help the court determine the truth of the matter at issue
expert witness
After a screening test has been used to determine the identity of an abused drug, the confirmation test of choice is thin-layer chromatography.
false
The ratio of length divided by width can be used to approximate the angle of impact of a single bloodstain.
false
sex determination - pelvis
female pelvis has the ilia spread wider than the male pelvis
ancestry determination from skeletal bones (recognize images)
femur and humerus
methods for height determination from skeletal bones
femur and humerus bones
The size of the specimen area in view is known as the _____.
field of view
The _____ amendment protects against self-incrimination.
fifth
When investigators search a fire scene, the first focus must be on:
finding the origin of the fire
IAFIS is a database for
fingerprints and criminal history
The combination of genes present in the cells of an individual is called the
genotype.
non-flammable liquid
glass vial
hard contact
gun is pressed hard against the skin - splitting of the skin as gases expand - soot deposits inside of the wound
tests for detecting primer residue on hands
gunpowder and primer residue also blows back toward shooter when a gun is fired • Early tests focus on the detection of nitrates from gunpowder • Diphenylamine color test- blue color indicated presence of nitrates • False positives possible since blue color is also present in • fertilizers, cosmetics, urine, and tobacco
layers of hair and the function of each layer
hair: an appendage of the skin that grows out of an organ known as the hair follicle. The lenght of a hair extends from its root or bulb embedded in the follicle, continues into the shaft, and terminates at the tip end. cuticle: the scale structure covering the exterior of the hair. Formed by overlapping scales that always point toward the tip end of each hair. Looking like shingles on a roof. Two features: 1. Resistance to chemical decomposition 2. Ability to retain structural features over a long period of time. The scale pattern not a useful characteristic for individualizing human hair. cortex: the main body of the hair shaft. Made up of spindle- shaped cortical cells aligned in a regular array, parallel to the length of the hair. 1. Embedded with the pigment granules that give hair its color. 2. The color, shape and distribution of these granules provide important points of comparison among the hairs of different individuals. Medulla: acellularcolumn running through the center of the hair. - The medullary index measures the diameter of the medulla relative to the diameter of the hair shaft and is normally expressed as a fraction. - Humans < 1/3; Animals > 1⁄2 - Classified continuous, interrupted, fragmented or absent. - Shape, human cylindrical root: the root and other surrounding cells within the hair follicle provide the tools necessary to produce hair and continue its growth
general classifications of firearms along with examples
handguns and long guns Handguns - Designed to be held and fired with one hand. e.g., pistols and revolvers. (Single action or Double action) Long guns - Designed to be fired while resting on shoulder. e.g., rifles and shotguns.
The following image is most likely a...
hard contact gunshot wound.
A comparative analysis determines if an item of evidence:
has a common origin with a reference specimen
E =
hf
The examination of physical evidence by a forensic scientist is usually undertaken for
identification or comparison purposes
evaluation
identification; exclusion; inconclusive.
analysis
identify any distortions associated with the friction ridges and any external factors
drug dependence: societal aspects of drug use
implications for the public ́s safety, health and welfare; society ́s decision to prohibit or control a drug's distribution and use (tobacco, coffee, alcohol, and marijuana)
natural causes
includes disease and continual environmental abuse
whorl fingerprint
includes ridge patterns that are generally rounded or circular in shape and have two deltas
verification
independent examination of the questioned and known prints by a second examiner
The product rule permits multiplication of the frequency of:
independently occurring evidence
striation markings from minute random imperfections in rifling are _____.
individual characteristics
blunt force trauma
injury to the body from a non-sharp or broad object (e.g., bat, pipe, hammer, brick etc.)
sharp force trauma
injury to the body from sharp weapons (e.g., knives and blades)
livescan
inkless device that captures digital images of fingerprints and palm prints and electronically transmits the images to an AFIS
process of rifling
inner surface (bore) of the barrel are impressed with spiral grooves creating lands and grooves. Allows for a spinning motion of a bullet which increases accuracy after being fired
The drug recognition expert (DRE) training program...
instructs participants on how to determine if a person is under the influence of one or more drugs.
emission spectrograh
instrument used to obtain and record the line spectra of elements
asphyxiation
interference with the intake of oxygen resulting in death; stoppage of breathing or the lack of air reaching the lungs
forensic pathologist
investigative personnel, typically medical examiners or coroners, who investigate the cause, manner, and time of death of a victim in a crime; can also be a physician who has been trained to conduct autopsies
schedule III
less potential for abuse than those in schedules I and II, a currently accepted medical use in the United States, and a potential for low or moderate physical dependence or high psychological dependence; controls, among other substances, all barbiturate preparations (except phenobarbital) not covered under schedule II, certain codeine preparations, and anabolic steroids.
Harder and nonporous surfaces result in _____.
less spatter
close
less than 6 inches soot from burned gunpowder and stippling from unburned gunpowder
Coherent radiation/light amplification by stimulated emission of radiation (LASER)
light that has all its waves pulsating in unison.
fingerprint dusting powder
lightly to a nonabsorbent surface with a camel's-hair or fiberglass brush, readily adhere to perspiration residues and/or deposits of body oils left on the surface; the magnetic-sensitive powder comes in black and gray and is especially useful on such items as finished leather and rough plastics, where the minute texture of the surface tends to hold particles of ordinary powder
Alcohol is oxidized in the body primarily in:
liver
thyroid cartilage
located below the hyoid
double loop
made up of two loops combined into one fingerprint
applications of the Stereoscope Microscope
magnifying powers from 10x to 125x; 3D image of an object; the prisms in is light path permit the formation of a right-side-up image; two monocular compound microscopes; used for trace evidence in debris, garments, weapons or tools.
sex determination - mandible (jaw)
male mandible - more upright; approximately 90 degrees female mandible - more slant; more than 90 degrees (obtuse)
sex determination - skull
male skull has larger size and more pronounced brow bone than female skull
The amelogenin gene shows 2 bands for a _____ and one band for a _____.
male, female
rigor mortis
medical condition that occurs after death and results in the stiffening of muscle mass; the rigidity of the body begins within 24 hours of death and disappears within 36 hours of death - evolves over the first 24 hours and disappears after 36 hours under average conditions - will develop in the position that the body was in at the time of death - can determine if body was placed in that position
An autopsy is performed by the...
medical examiner or pathologist.
A bloodstain with a diameter of 2mm could be classified as _____.
medium-velocity spatter
arson evidence
metal can
inorganic substances examples
metals, salts, glass, paint pigments, bullets/casings
quadrant/zone search pattern
method is best suited for scenes that cover a large area, must include all probable points of entry and exit used by the criminals
wheel/ray search pattern
method is not preferred because the areas between the "rays" are not searched
Tests to identify specific substances by the color and morphology of the crystals formed when the substance is mixed with specific reagents is referred to as...
microcrystalline tests.
analytical methods for identifying and comparing manufactured fibers
microscopic examination for color, diameters, lengthwise striations on the surface, cross-sectional shape dye composition with microspectrophotometer and thin-layer chromatography chemical composition with birefringence and IR spectrum
Walter McCrone was a famous criminalist who advocated the use of _____ to solve forensic problems.
microscopy
Mitochondrial DNA is inherited from our _____.
mother
product rule
multiplying together the frequencies of independently occurring genetic markers to obtain an overall frequency of occurrence for a genetic profile
The search for physical evidence at the crime scene
must be thorough and systematic
schedule V
must show low abuse potential, have medical use in the United States, and have less potential for producing dependence than schedule IV drugs; controls certain opiate drug mixtures that contain nonnarcotic medicinal ingredients
_____ fibers are derived totally from animal, mineral, or plant sources.
natural
drug
natural or synthetic substance that is used to produce physiological and psychological effects in humans or other higher-order animals
physical dependence
need for a drug that has been brought about by its regular use; dependence is characterize by withdrawal sickness when administration of the drug is abruptly stopped
distant
no stippling or soot
The use of fingerprint powder is preferred for development of latent prints on _____ surfaces
non-porous surfaces
homicide
nonaccidental death resulting from grossly negligent, reckless, or intentional actions of another person
black powder
normally, a mixture of potassium nitrate, carbon, and sulfur in the ratio 75/15/10
accidental
not be intent to cause harm through gross negligence on the part of a perpetrator or the victim
tented arch
nstead of rising smoothly at the center, there is a sharp upthrust or spike, or the ridges meet at an angle that is less than 90 degrees
firearm evidence - class characteristics
number of lands and grooves and approximate width and direction of twist
The lens closest to the specimen is called the _____.
objective lens
plain whorl loop
one ridge that makes a complete circuit
discovery
one side in litigation seeks to gather information about testimony and evidence that is in the hands of the other side
Aperture
openings on pollen grains from which the pollen tube grows and carries the sperms to the egg to complete fertilization
Which chemical reaction is associated with a fire?
oxidation
elimination
oxidation and excretion
Physical evidence from an arson scene should be:
packaged in airtight clean paint cans
As a matter of routine, all items of clothing are to be _____ before submitting.
packaged separately
Biological evidence at crime scene, such as blood, should be collected and packaged in
paper
biological evidence (semen, blood, plants)
paper bag/envelope, airdrop and package separately
trace evidence (hair, glass, fibers, soil, paint)
paper fold/bindle, unbreakable plastic bottles, manila envelopes, screw-cap glass vials, cardboard pillboxes
absorption
passage of alcohol across the wall of the stomach and small intestine into the bloodstream
For documenting bloodstain pattern evidence, the method that involves setting up a rectangular border of rulers around the pattern is known as the _____.
perimeter rule method
DNA fingerprinting
process of isolating and reading markers of DNA (Alec Jeffreys)
Pollen Rain
production and dispersal patterns of spores and pollen
collecting evidence
properly packaged, sealed, labeled, separate packages, keep items in original condition
stab wound
puncturing wounds perpendicular to the skin - wound is deeper than it is wide - more lethal
chemistry of fire - combustion
rapid combination of oxygen with another substance, accompanied by production of noticeable heat and light
undetermined
rational classification cannot be established
Fingerprints are an example of...
real evidence.
Enzymes known as DNA polymerase assemble new DNA strands into a proper base sequence during the _____ process.
replication
Numerical aperture (N.A.) measures the ability of an object lens to _____ details into separate images.
resolve
plastic prints
ridge impressions left on a soft material such as putty, wax, soap, or dust
loop fingerprint pattern
ridge lines that enter from one side of the pattern and curve around to exit from the same side of the pattern
_____ is the process by which the inner surface (bore) of the barrel are impressed with spiral grooves.
rifling
toxicology report
samples of blood, stomach content, bile, and urine - determine the presence of alcohol or drugs
what is the main ingredient in ordinary glass?
sand (silicon oxides)
abrasions
scraping of the skin by a rubbing or shearing force
A test that is nonspecific and preliminary in nature is a...
screening test.
screening vs confirmatory drug testing
screening tests: presumptive, quick, convenient, cheap, tentatively identify drugs - thin layer chromatography (TLC) - gas chromatography (GC) - immunoassays confirmatory drug tests: gas chromatography / mass spectrometry (GC/MS)
wipe patterns
secondary object moves through a bloody stain on another object
general goals of processing a crime scene
securing and isolating the crime scene, recording the crime scene, conducting a systematic search for evidence
_____ contains removable magazine containing cartridges which are loaded in the grip of the firearm.
semiautomatic handguns
The _____ of a skeleton can be determined by observing the shape of the pelvis and sacrum, the size of the cranium, and the protrusion of the brow bone and mastoid process.
sex
The _____ of bloodstains may provide useful information regarding the direction, dropping distance, and angle of impact of pattered blood.
shape
calculating the angle of impact
sin^-1(W/L) "sin^-1" = inverse sine width of a stain is 11 mm and the length is 22 mm angle of impact = Sin^-1 (11/22)= Sin^-1 (.5)= 30-degree angle
states of matter
solid, liquid, gas (vapor)
All of the following are chromatographic processes found to be applicable for solving analytical problems encountered in the crime laboratory except...
solid-state chromatography.
Semen is unequivocally identified by the microscopic appearance of _____.
spermatozoa
applications of the Polarizing Microscope
studying materials that polarize light; studies many crystalline substances are birefringent; that is, they split a beam of light into two light-ray components of different refractive index values. The light beams are polarized at right angles to each other, thus finding wide application for the examination of birefringent minerals present in soil. Similarly, criminalists use the fact that many synthetic fibers are birefringent to characterize them.
changes in states of matter
sublimation, deposition, condensation, evaporization, melting, freezing
An order issued under the direction of a court commanding the presence of a witness at a specific time and place to give testimony or other evidence is referred to as a _____.
subpoena
organic
substance composed of C and H and often smaller amounts of N, P, O,S, F, Cl, Br, I and other elements.
Uncontaminated surface material close to an area where physical evidence has been deposited is a:
substrate control
microcrystalline tests
tests to identify specific substances by the color and morphology of the crystals formed when the substances are mixed with specific reagents. Size and shape characteristic of the drug
in comparing two hair samples, the forensic scientist is not interested in matching which of the following aspects?
texture
a bright halo that is observed near the border of a particle immersed in a liquid of a different refractive index is known as
the Becke line
chemistry of fire - energy
the ability or potential of a system or material to do work
Forensic Science is defined as:
the application of science to civil and criminal laws
forensic science
the application of science to law; he knowledge and technology of science to the definition and enforcement of such laws
The string method is used to determine
the area of origin using bloodstain pattern.
field of view
the area of the specimen that can be seen after it is magnified
chemical properties
the behavior of a substance when it reacts or combines with another substance.
physical properties
the behavior of a substance without alteration of the substance ́s composition through a chemical reaction.
asphyxiation - hyoid bone
the bone on which the tongue rests; thyroid cartilage not fractured during hangings
agglutination
the clumping together of red blood cells by the action of an antibody
chemistry of fire - oxidation
the combination of oxygen with other substances to produce new substances
oxidation
the combination of oxygen with other substances to produce new products - 95-98% oxidized to carbon dioxide and water in the liver
The form and pattern of a fingerprint is determined by:
the dermal papillae
The pointed end of a bloodstain faces _____.
the direction of travel
wavelength
the distance between crests of adjancent waves (λ).
chemistry of fire - flammable range
the entire range of possible gas or vapor fuel concentrations in air that are capable of burning
electromagnetic spectrum
the entire range of radiation energy from the most energetic cosmic rays to the least energetic radio waves.
plasma
the fluid portion of unclotted blood
Probability is defined as:
the frequency of occurrence of an event
how the shape of blood is affected by surface texture, angle of impact and direction of travel
the harder and less porous the surface, the less spatter results; the pointed end of a bloodstain always faces its direction of travel; as angle decreases, stain becomes elongated
The minimum temperature at which a fuel will spontaneously ignite is called:
the ignition temperature
applications of the Scanning Electron Microscope
the image is formed by aiming a beam of electrons onto the specimen and studying electron emissions on a closed TV circuit. The beam of electrons is emitted from a hot tungsten filament and is focused by electromagnets onto the surface of the specimen. This primary electron beam causes the emission of electrons, secondary electrons, from the elements that make up the upper layers of the specimen. 20-30% of the primary electrons rebound off the surface, backscattered electrons. High magnification, high resolution and great depth of focus. 10x to 100,000x.
calculating total magnification for the compound microscope
the multiplication of the magnifying power of the objective and eyepiece lenses
atomic number
the number of protons in the nucleus of an atom; each element has its own unique atomic number.
frequency
the number of waves that pass a given point per second (F).
radioactivity
the particle and/or gamma- ray radiation emitted by the unstable nucelus of some isotopes
electron orbital
the path of electrons as they move around the nuclei of atoms; each orbital is associated with a particular electronic energy level
direction of travel of satellite spatter
the pointed end facing against the direction of travel
comparison
the process of ascertaining whether two or more objects have a common origin
identification
the process of determining a substance's physical or chemical identity. Drug analysis, species determination, and explosive residue analysis are typical examples of this undertaking in a forensic setting
distance determination from gunpowder residue
the process of determining the distance between the firearm and a target, usually based on the distribution of powder patterns or the spread of a shot pattern. • as distance increases, less residue deposited • spread and density vary between weapons • suspect gun or gun of the same type needed for accurate analysis
refractive index
the ratio of the speed of light in a vacuum to its speed in a given substance.
dispersion
the separation of light into its component wavelengths.
atom
the smallest particle of an element that can exist and still retain its identity as that element.
c
the speed of light in a vacuum is a universal constant at 300 million meters per second.
area of origin calculated
the string method: 1. Find the area of convergence for the stain pattern. 2. Place a pole or stand as an axis coming from the area of convergence. 3. Attach one end of a string next to each droplet. Place a protractor next to each droplet and lift the string until it lines up with the determined angle of impact of the drop. Keeping the string in line with the angle, attach the other end of the string to the axis pole. 4. View the area of origin of the drops where the strings appear to meet. Secure the strings at this area.
serology
the study of antigen-antibody reactions
forensic entomology
the study of insect matter, growth patterns, and succession of arrival at a crime scene to determine the time since death - time of death estimation - developmental stage of fly used to estimate postmortem interval - best estimation from hours to approximately 1 month after death - can be affected by location, weather presence of drugs
Forensic Palynology
the study of pollen and spore evidence to help with crime scenes, illegal activities, or terrorism
atomic mass
the sum of the number of protons and neutrons in the nucleus of an atom.
depth of focus
the thickness of a specimen that is entirely in focus under a microscope
conduction
the transfer of heat or electric current from one substance to another by direct contact
convection
the transfer of heat through a fluid (liquid or gas) caused by molecular motion
metabolism of alcohol
the transformation of a chemical in the body to another chemical to facilitate its elimination from the body
The weight or significance accorded physical evidence in a courtroom is left to
the trier of facts, usually a jury of laypersons
nucleotide
the unit of DNA consisting of one of the four bases adenine (A), guanine (G), cytosine (C), or thymine (T)-attached to a phosphate-sugar group.
forensic anthropology
the use of anthropological knowledge of humans and skeletal structure to examine and identify human skeletal remains - examination of human skeletal remains to identify individuals - skeletal bones disintegrate slowly allowing for examination decades or centuries later - provide information on a victim's sex, approximate age, race , height and type of injury.
the dye components removed from fibers can be separated and compared by _____ chromatography.
thin-layer
Algor Mortis, Rigor Mortis and Livor Mortis are processes that can be used to determine the...
time of death.
objective of toxicology of alcohol
to detect and isolate drugs in the body so that their influence on human behavior can be determined.
field sobriety testing methods
to determine degree of impairment and whether evidential (confirmatory) test is justiied - breath testing - psychophysical tests like horizontal gaze nystagmus, heel-to-toe walk and turn, one-leg stand (and count)
The most important prerequisite for photographing a crime scene is?
to keep it unaltered
The examination of body fluids and organs for drugs and poisons is the function of the _____ unit.
toxicology
optional services of a crime lab
toxicology unit, latent fingerprint unit, polygraph unit, voiceprint analysis unit, csi unit
swipe transfer patterns
transfer of blood onto a surface by a bloody object that is moving
Transmitted illumination is used when the specimen being examined is?
transparent
The Daubert standard for admissibility of evidence allows the _____ to act as the "gatekeepers".
trial judges
A breath test, used to measure alcohol, reflects the alcohol concentration in the pulmonary artery.
true
A person with a BAC of 0.40 can fall in a comatose state.
true
At an arson scene, the collection of a substrate control would require the collection of a piece of the surface material near the fires origin believed not to have been exposed to the accelerant.
true
Gasoline residues are best characterized by Gas Chromatography.
true
Iodine prints are not permanent, therefore, the examiner must photograph the prints immediately on development in order to retain a permanent record. However, if the developed print is simply covered with a clear cellophane tape soon after development, will be usable for at least several months. Also, iodine- developed prints can be fixed with a 1 percent solution of starch in water, applied by spraying. The print turns blue and lasts for several weeks to several months.
true
Schedule III drugs have accepted medical use, an average potential for abuse, and may lead to high psychological dependence.
true
fume with iodine then ninhydrin then physical developer
true
it is possible to determine if hair was forcibly removed from the body
true
applications of the Comparison Microscope
two compound microscopes combined into one unit; uses a bridge incorporating a series of mirrors and lenses to join two independent objective lenses into a single binocular unit; used for bullets, cartridges and other opaque objects, vertical or reflected illumination, hairs or fibers, transmitted illumination.
mass spectrometry is a useful technique for comparing and identifying unknown compounds because?
under carefully controlled conditions, no two substances produce the same fragmentation pattern.
strip/line search pattern
used in scenes where the boundaries are well established, because the boundaries dictate the beginning and end of the search lines
grid search pattern
very thorough, but the boundaries must be well established in order to use this method as well
Locard's Exchange Principle
whenever two objects come into contact with one another, there is exchange of materials between them
Rule 702
witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if; (a) The expert's scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) The testimony is based on sufficient facts or data (c) The testimony is the product of reliable principles and methods AND (d) The expert has reliably applied the principles and methods to the facts of the case
which of the following is not a man-made fiber grouping?
wool
which of the following types of light has the most energy? (high energy = highest frequency = shortest wavelength)
x-rays
identify natural and manufactured fibers
Ø Natural Fibers. Fibers derived entirely from animal or plant sources. Include hair coverings from animlas like sheep (wool), goats (mohair, cashmere),... Same procedure as hair examination. Standard/reference samples. Most prevalent Cotton. Ø Manufactured Fibers. Fibers derived from either natural or synthetic polymers; the fibers are typically made by forcing the polymeric material through the holes of a spinneret. Rayon, 1911, Nylon, 1939. Ø Regenerated Fibers. Fibers manufactured from natural raw materials. Rayon, acetate and triacetate from regenerated cellulose. Ø Synthetic Fibers. Produced solely from synthetic chemicals. Nylon, polyesters, and acrylics.
automated firearms search systems
• NIBIN-National Integrated Ballistics Information Network • CMS- system used for matching bullets and toolmark
polymerase chain reaction steps involved
• Primer- A short strand of DNA used to target a region of DNA for replication by PCR. • Hybridization- The process of joining two complementary strands of DNA to form a double-stranded molecule • Denaturing (94°C) - Separates the DNA into single strands • Annealing (60°C) -Primers anneal to the template DNA • Extension (72°C) - DNA Polymerase extends the new strands by adding free nucleotides
role of gunpowder residue in ammunition
• burned and unburned gunpowder ignites creating an explosion producing expanding gases that propels the bullet out of the barrel.
methods for lifting and preserving dust impressions
• preservation techniques • photograph with scale before handling or moving lifting: analogous to latent fingerprints portable electrostatic lifting device used to recover barely visible dust prints on colored surfaces chemical development to preserve dust impression: bromophenol blue
DNA replication and the steps involved
•Begins with unwinding of the DNA strands •Free nucleotides re-create the double helix •Results in two identical copies of DNA •Requires many enzymes & proteins • Unwind strands • Keep strands apart • Assemble the new strands • DNA polymerases • Also checks for mismatched base pairs