Practical Crime Scene NOTES

DNA basic info

- 23 pairs chromosomes, each parent contributes one half - approx. 10,000 genes define every trait - Guanine & Cytosine - Adenine & Thymine

near-UV and violet//blue light (415-485nm)

- 450 w/ yellow filter = bite marks and bruises on human skin - 455-485 w/ yellow or orange filter = fluorescein reactions with blood - 485 w/ yellow filter = fingerprints developed with ninhydrin

buried and scattered remains

- NecroSearch International - magnetometers - ground-penetrating radar - infrared thermography - probes - vapor monitors

criteria for pattern transfer

- a contact pattern - demonstrating angular demarcations, curves, or other recognizable characteristics or an images of the source object - may be deposited in a series

criteria for gush//splash

- a large volume accumulation evidence in the overall pattern - large irregular stain exhibiting spines and satellite spatter radiating from it - there may be large elliptical spatter stains around the pattern

criteria for blood into blood

- a pooling of blood or some combination of blood and some other liquid that may exhibit evidence of overlapping drips - surrounded by a random distribution of small satellite spatter - the surrounding satellite spatters will show random variation in their directional angles and shapes

criteria for impact

- a series of related small spatter stains - deposited in a pattern that has a radiating distribution in some fashion - with a progressive change in individual stain shape the further out in the pattern - various size range of parent stains, but generally consistent throughout the pattern

criteria for cast-off

- a series of related spatter stains - deposited in a linear or curvilinear orientation - with consistent parallel directional angles in the stains to the overall pattern - a consistent change in impact angle in the pattern

photographic composition

- accomplished organization of the space and items depicted in the photo so that the various visual elements relate to one another properly - controlling contrast - properly framing the subject - maintaining simplicity - Gardner = NOT using Rule of Thirds

crime repression

- actively investigative crimes - attempting to identify and apprehend subjects

entomology

- activity begins almost immediately - flies lay eggs within 20 minutes of death in warm, moist areas - maggot mass on unexpected location such as chest or extremities may indicate that that area was injured pre- or ante-mortem

bloody prints

- amido-black - leuco-crystal violet - alcohol-based fluorescein - patent prints can be photographed and lifted as is, or enhanced with powder and lifted

primary mechanisms of injuries

- asphyxia - sharp force trauma - blunt force trauma - gunshot trauma

fire scene methodology

- assessment of exterior - work from least damaged areas to most damaged - rules of thumb - examination is best conducted by evaluating specific fire burns independently of other patterns and evidence - no one fire sign will tell the entire story - consult with local fire marshal and fire department members be objective

steps to conduct bloodstain spatter analysis

- become familiar with entire scene - identify the discrete patterns among the various bloodstained surfaces - classify patterns based on the physical characteristics using some for of established taxonomy - evaluates aspects of directionality and motion in the stain or pattern - evaluate angles of impact, points of convergence, and areas of origin - evaluate interrelationships among stains, patterns, and other evidence - evaluate viable source events to explain the pattern - validate the analysis through some form of peer review

computer and media systems analyses

- determining content of drives and media - comparing data files - establishing when a file or action was created or conducted - recovering deleted information and files - decrypting password-protected systems, files, or media

factors influencing gunshot injuries

- distance of the victim to the firearm - area of the body where the wound was created - whether the area is free or supported by clothing or other external object - caliber of size of the projectile - velocity of the projectile - amount of fragmentation or deformation of the bullet - type of projectile

why would an officer be required to accompany a victim to the hospital

- document any dying declarations - spontaneous utterances - collect evidence from victim

buried and scattered remains methodology

- document overall surface context in and around - establish grid - all measurements are made in relation to the grid - examine with metal detector - remove loose debris by hand - cut ground plants at surface - use screens to sift through all litter, debris, and soil - stratification//superposition of obvious layers or significant artifacts - use trowels and brushes once the fill is found - measure item's elevation in relation to the grid, as well as where in the grid it is - keep dig "in phase"

soil - environmental variation

- pollens (easily identified by their structure) - content of soil - quantity of various minerals and substances - color - consistency

hazards must be assessed for two specific issues

- potential effect of the hazard to both personnel and the mission - how probable or likely it is that the hazard will occur

Five ways in which context manifests itself in the crime scene

- predictable effects - unpredictable effects - transitory effects - relational detail - functional detail

initial responding officer's barrier should include...

- primary focal points - natural entry and exit points - secondary scenes

chemical tests for verifying bullet defects

- primer residue (barium, antimony, and lead) - lead presence - copper presence - nitrite presence

indanedion

- produces higher-quality results - works better on hard-to-process surfaces like currency - greater detail in fluorescence print - requires cyan light w/ orange filter (in 475nm range)

protection of personal liberty

- protect citizens from unwanted police interference of their personal liberties

seven observational conditions of life

- pulse in major arteries - heartbeat - respiration - evident body heat - constriction of pupils in response to light - flushing of nail beds - movement or an ability to react to simuli

eight-step descriptive set

- quantity - item - color - type of construction - approximate size - identifying features - conditions - location

glass direction of force

- radial fracture - concentric fracture - conchoidal fracture - 4R rule

ridge identification is based on at least 15 different ridge characteristics

- ridge endings - bifurcations - short ridges - enclosures - ridge dot - ridge break - angular formations (deltas) - overlap - spurs - bridges - trifurcations - crossings - changeovers - ridge punch - loops

impression evidence casing methods

- rubberized casting compounds - electrostatic dust lifts - plaster and dental stone - gelatin and adhesive lifters

purpose of debriefing and assessment by investigative team

- scope of the scene - scene integrity and contamination control - team approach and composition - search methods to be used - personal protective measures

three crime scene integrity issues

1 - addition of material to the scene (post-incident artifacts) 2 - destruction of material in the scene 3 - movement of material in the scene

six basic steps for crime scene processing

1 - assessing 2- observing 3 - documenting 4 - searching 5 - collecting 6 - analyzing

two primary goals of initial responding officer

1 - bring the site under control 2 - coordinate resources

five basic objectives to bring site under control and coordinate resources

1 - document the provided information 2 - not become a casualty 3 - provide for emergency care 4 - secure and control the scene and all those within it 5 - release the scene to appropriate authorities

five key ingredients to a good crime scene examination

1 - knowledge 2 - skills and tools 3 - methodical approach 4 - flexibility 5 - coordinated effort

Bevel & Gardner = four questions the investigator should ask about evidence

1 - what is it 2 - what function did it serve 3 - what relationship does it have to any other items of evidence or to the scene itself 4 - what does it tell us about timing and sequencing aspect

steps of roadmapping

- recognition of discrete patterns or defects - placement of appropriate labels and scales - creation of overall photos of an area with labels in place - creation of overall photos of a pattern with sublabels in place - creation of additional evidence-establishing photos of individual stains or details when needed - creation of close-up photos of individual stains, defects, or details with sublabels or subsublabels

express purpose of crime scene processing

- recovering physical evidence - documenting the scene's condition in situ

pros of Total Station

- requires no reference to magnetic north, due to the accuracy of measurements - ability to measure distance to within a few millimeters and angle to a precision of 0.0013888°

CSR - relationship

Locard's Principle of Exchange, but broader - through associations of evidence we establish relationships between various items of evidence - logical - special - temporal

"Before the detective or investigator can successfully conduct a search for evidence, he must know what he is searching for"

Luke S. May, 1933

"A fire or explosion investigation is a complex endeavor involving both art and science. The compilation of factual data, as well as an analysis of those facts, should be accomplished objectively and truthfully... With few exceptions, the proper methodology for a fire or explosion investigation is first to establish the origin(s), and then investigate the cause"

National Fire Protection Association's Guide for Fire Explosion Investigations

functional approach scene team - evidence collection

2 people minimum

functional approach scene team - photography scene

2 people minimum

functional approach scene team - search team

2 people minimum

functional approach scene team - sketch and measurements

3 people minimum

CSR - continuity

Nikolas Steno's Law of Lateral Continuity - strata are not deposited in a way in which they abruptly end: thus when presented with disassociated strata or artifacts, they can by their similarities be considered to be from the same depositional period - void in spatter - continuity or lack thereof is a major indicator to the analyst - disruption or lack of disruption of various surfaces or deposits in scenes will assist the crime scene investigator in recognizing if something happened as claimed

"Lab Rats and Field Mice" must understand each other's role and must work together in order to achieve truth

Bruce Wiley, 2003

"absence of evidence is not evidence or absence"

Carl Sagan

swabbing

Dacron//Polyester swabs preferred over cotton because they hold up better - have no electrical charge that may interfere with the DNA extraction process at the lab - use isopropyl alcohol instead of water

T or F: The range determinations offered by the medical examiner are all based on the absence or presence of soot, stippling, and burning in or around the wound

False

T or F: Where each and every bullet defect is located is not of significant interest and bullet holes do not have to be located in the sketch and crime scene mapping data

False

T or F: The wake effect observed in metal and "metal splash" are observations that help the crime scene analyst determine in what sequence bullets were fire

False (help determine direction of fire)

T or F: Identification of a firearm to a bullet is accomplished by evaluating the lands and grooves found in the bullet

False (individual striations)

CSR - superposition

Nikolas Steno's Law of Superposition - geologic strata are deposited in a time order, oldest to youngest unless otherwise disturbed - the order of deposition of all of these items tells us something about what was happening in the scene and the order that it happened

"As forensic investigators, limiting ourselves to evidence which is only visible under the visible light spectrum would be like refusing to allow a criminalist to use a microscope in trace evidence examination"

Houseman and Maloney

cartridge

a complete unit of unfired ammunition - casing, primer, propellant, bullet

tracings

a conscious effort to copy a known writing - can often see hesitation marks

risk management

a deliberate effort to identify hazards, assess the significance of those hazards, and then implement controls to mitigate the risk and reduce the possibility of injury or harm

area approach crime scene team

a single team handles all activities associated with processing for a given area

smear - wipe

a smear through a preexisting stain or pattern

smear - swipe

a smear when blood is deposited onto the surface

functional approach crime scene team

a team leader designates different teams to do different activities

testing for copper presence in bullet defects

aka dithio oxamide (DTO) or Cuperotesmo - filter paper twice the size of the defect is moistened with 2:5 solution of ammonia to dithio oxamide, then pressed to the defect - spray the paper with a solution of 0.2% DTO in ethanol - positive reaction = green

T or F: The deformation of a bullet as it strikes a target at an acute angle may allow the firearms analyst to determine the angle of deflection

True

cyanoacrylate fuming

fumes of the glue react with the print, plasticsizing and stabilizing the print - can be dyed - locks the print to the surface - does not greatly affect DNA, drug ID, or firearm examinations - can affect trace evidence examinations

forensic linkage triangle

function is to remind the investigator that each item discovered must be considered a mechanism for linking the scene, the victim, or the suspect - evidentiary value, or explainable through some other innocent mechanism

reports - 2 characteristics of the scene

general description of the area and associated features - doors - windows - openings - geographical features of outdoor scenes and relationship to surrounding area - furniture - appliances - other artifacts

latent prints

generally invisible, created by the deposit of normal body secretions

clinical pathologist

generally works at a hospital and is concerned with determining the cause of death

PDP - blood dispersed as a function of gravity

gravity draws the fluid downward until the weight overcomes the surface tension of the fluid, and it drops - produces primary droplet and satellite droplets - drip - drip trail - blood into blood - source may be replenishing or non-replenishing

bullet trajectory - angle of departure

horizontal = angle of the muzzle in relation to the target using horizontal reference line (movement left and right)

fire "cause"

how the fire started

asphyxia - strangulation

hypoxia of the brain - sufficient pressure to cut off major arteries serving the brain

EA Step 3: Define associated event segments

analyst looks for associations between the various event segments and events - breaking the mas of data into manageable chunks of information

area or origin evaluations

analyst needs close up photos of 10-15 individual elliptical stains and must know where those stains were on the surface involved - located core of pattern and mark it - measure forward from this point to the end of the primary patterns - break primary pattern into two parts - split the two sections into four areas - result is 4-6 distinct areas to photograph - place ABFO scale and identifier in each area, with as many symmetrical and elliptical stains as possible (6-10 ideally)

EA Step 4: Order and sequence the associated event segments

analyst will develop a mosaic of logical order to the majority of event segments by combining interrelationships - absolute chronology - relative chronology - terminus ante quem - terminus post quem - terminus peri quem

ACE-V

analyze compare evaluate verify

non-porous smooth surfaces

any surface that does not absorb moisture - varnished and painted surfaces - plastic - glass - metals - ceramics

grid search

area is divided into two sets of 90° to each other and searched

reports - 8 search for latent prints

areas where it was attempted, whether positive or negative results, and nature of prints

blunt force injuries - contusions

bruises, resulting from damage to blood vessels in or around the area of injury - can occur to organs

grazing bullet wounds

bullet leaves only a minor abrasion as it passes adjacent to body

tangential bullet holes

bullet skims a surface creating a series of defects

ricochet or deflection bullet defects

bullet strikes a surface and deflects off it at some angle without penetrating the surface entirely

single bullet defect on a solid substrate without sufficient penetration for rodding

calculating the impact angle using the mathematical method will provide a parameter of possible flight paths

rubberized casting compounds

can be used to get powdered prints off of curved surfaces - commercial products are better than those from a hardware store - beset on hard substrates like metal, wood, bone, or plastic - not effective for bite impressions or casting dirt impressions - vital to thoroughly mix the compound elements

patent prints

caused by the deposit of contaminants (blood, grease, etc.) that are visible to the naked eye

striations

caused when the cutting edge of a tool is brought in contact with and slide against a target surface

asphyxia - drowning

cerebral anoxia - water invades the lungs, preventing oxygen from entering the bloodstream - vocal chord spasm is possible - physical findings are very limited and dependent on the condition of the body

asphyxia - positional or mechanical

cerebral hypoxia - person is incapable of breathing normally - often accidental, but homicidal actions can produce the same result - common findings: red or purple color of the face and neck; petechial hemorrhages of the sclera and conjuctivae

1, 8 diazfluoren (DFO)

chemical reaction with amino acids - fluorescent orange - can be visualized using cyan light w/ orange filter (490-520nm)

ninhydrin (triketohydroginhydrate)

chemical reaction with amino acids - purple prints - fugitive, unless a fixative is used - often depletes all of the amino-acids - can be visualized with cyan light w/ orange filter (490-520nm), green light w/ orange or red filter (520-550nm), or amber light w/ red filter (588-595nm)

iodine

chemical reaction with fatty acids - dark brown prints - fugitive, so must be photographed quickly - very corrosive and produces harmful vapors - works well on fresh prints

What is the basic goal of crime scene processing?

collection of evidence and scene context in as pristine condition as possible by assessing, observing, documenting, searching, collecting, and analyzing

short tandem repeat (STR)

combined concepts of PCR, but created statistical discrimination that was higher than that developed through RFLP, so both degraded and small samples could be examined to the point of individualization - post-incident artifacts or cross-contamination are big concerns

testimonial evidence

comes from interviewing and interrogating victims, witnesses, and suspects - humans are subjective, and more likely than not, any failures in testimony is not deceitful in nature

slack space

computers are inefficient in storing information - often using much larger areas to store a file than is necessary

Bloodstain Pattern Analysis: With an Introduction to Crime Scene Reconstruction...Practical Crime Scene Analysis and Reconstruction, Gardner & Bevel (1997 and 2009)

concise and specific methodology

traced writing

conscious effort to copy a known writing - lacks fluid moments - might be able to see hesitations in the middle of letters

the relationship between stain shape and the vector correlation

considered together, the impact and directional angles for a number of stains associated with an impact event may define the origin of the stains in three dimensions

forgery

considers a known writing and attempts to identify the writer

small particle reagent

consists of molybdenum disulfide suspended in a water solution - spray on wet surface - rinse - allow to dry - lift like normally powdered print - might work on concrete, cinder blocks, natural rocks, sytrofoam, and stucco

risk control and mitigation

control measures are considered as a means of reducing the probability that the hazard may occur, or reducing the effect of the hazard on personnel

non-spatter - pattern transfer

created by the transfer of blood from one object to another in which recognizable characteristic or image is present in the pattern

blunt force injuries

crushing of associated tissue, and typically occur in combination with one another - abrasion - contusions - lacerations

sharp force injuries - stab wound

deeper than it is long - characteristics are dependent on the shape and size of the edged weapon, as well as the direction and force applied - unusual bruising or markings at the point of injury may occur from the weapon configuration (hilt marks, etc.)

Peter Lamb, UK's home office forensic science unit

defined the reconstructive process as involving four phases - information = considering the initial known information in an effort to define investigative questions - observation = collection of specific data regarding the problem - interpretation = correlating the information and observations, challenging observations, and looking for valid hypotheses - conclusions = a matter of testing hypotheses and eliminating those that can be objectively eliminated

plaster and dental stone casting

dental stone is preferred over plaster because it sets harder, is more forgiving of error during mixing, and tends to recover more detail - can cast tow-dimensional prints on concrete by using magnetic powder on the print, then casting - can spray with dark colored spray paint before photographing to give better contrast

reports - 6 scene documentation

describe the basic efforts taken to photograph and sketch the scene

reports - 7 collection of physical evidence

description of what was seized and where it was found

Scan Station

designed to automatically scan and record literally millions of points in an arc of 360° and 270° around the system - captures a panoramic images of the survey, which is correlated to the physical points

how does the f-stop affect resulting photography

determines how wide the lens aperture opens, thereby controlling the amount of light the film//sensor is exposed to - the higher the f-stop, the smaller the aperture, resulting in the introduction of less light

turning diameter

diameter of the circle created when the front axle is turned to its full extent

hairs and fibers

distinguishes first by species, then general race as well as location from the body

porous surface processing

dry paper (DFO, ninhydrin, silver nitrate) dry untreated wood (ninhydrin, powder//brush) wet surfaces (seize and dry, then physical developer)

non-porous smooth processing

dry surface (cyano, powder, SPR, silver nitrate, iodine) wet surface (SPR, or seize and dry, then any of above)

non-porous rough processing

dry surface (cyano, powder, silicone-based casting material or textured surface lifting tape//material) wet surface (seize and dry, then above processing)

"layer cake" effect of landfills

dump the load, compact it, cover with approximately 1' clean dirt

polar coordinates

effective for mapping exterior scenes in which the evidence is significantly scattered over a relatively open area, where all items are in view (based on surveying techniques) - horizontal angle = measured as rotation of the sighting instrument from north in the horizontal plane, a measurement of 1-360° - horizontal distance = measured as the distance between the datum point and the evidence item - difference in elevation = difference in height from a benchmark (datum point elevation) and the evidence - sighting device at the datum point must be higher than the evidence - determine the distance between the datum point elevation and the sighting instrument, which is then subtracted from the elevation reading to establish the actual elevation distance between the datum point on the ground and the evidence

spatter - spurt

ejected in a stream under pressure or with velocity, most often when an artery or the heart is breached - often help the technician in understanding the movement or orientation of a victim subsequent to significant injuries

Zones of Possibility

eliminating areas where something could not have happened and identifying areas where it could have happened has value, even when the technician cannot isolate the event to an exact position - zones 1-3

concentric fracture

encircle the central area of the fracture at various distances

perforating bullet wounds

enters and exits

perforating bullet holes

enters and exits a surface//object

penetrating bullet wounds

enters but does not exit

penetrating bullet holes

enters but does not exit a surface

direction of fire in glass surfaces

entry = abrupt edge exit = sloping or coning effect; displacement of glass

Restrictive Fragment Length Polymorphism (RFLP)(1987)

evaluated several loci, and from this comparison it was able to provide significant discrimination between samples - but...relied on large and undegraded samples

terminus peri quem

events that must have been simultaneous

terminus post quem

events that must have followed another event segment

terminus ante quem

events that must have preceded another event segment

CSR - chronology

every action has something that naturally precedes or follow it - every action occurring in the scene is considered against all other actions to determine if it precedes, follows, or is simultaneous to those actions - sequence = evaluated using three simple logical relationships - time = less evidence, but items such as cameras and receipts can be helpful

when is it appropriate to slow or stop EMS from entering a crime scene

evidence of putrefaction of the victim, headless body - officer should accompany one EMS to the body to confirm death

inner perimeter boundary

extends around the area considered to be the actual scene - limited access to crime scene personnel, case detective, and ME investigators

techniques for fire scenes

fire scenes often hold outstanding print evidence that is nearly indestructible - heat seems to bake the print in place as well as react with the soot to create pigmentation that makes the latent visible - examine metal and glass, then wash gently with tap water - may be necessary to enhance with powder - it's possible that the salts and moisture in the print causes it to corrode the metal (differential oxidation) - might have same effect on bullet casings

rectangular coordinates

fixes the evidence by measuring at right angles from the evidence to the surrounding walls and surfaces - best used for clear and specific boundaries (interior scenes) - fast and effective - not as precise as other methods, as the measurement is taken from center mass

triangulation

fixes the evidence by measuring from two distinct landmarks to two distinct points on the item - for irregularly-shaped items, take two measurements from the center mass, plus a measurement of the overall width of the item - do not triangulate from items that themselves are fixed in the scene with triangulation

EA Step 7: Final flowchart of the overall incident based on the event and event segment sequence

flowcharting= graphically representing the order of the event segments - validate the flowchart - end product is a defined outline of what can objectively be concluded as having occurred during the incident

sexual assault nurse examiner (SANE)

forensically trained medical professional capable of collecting clothing and various forms of evidence as well as documenting specific injuries, no matter where they are located

heat energy and thermal imaging (12,000nm)

forward looking infrared radar (FLIR) - identify travelers with raised temperatures as a means of spreading infectious disease - distinguish between old and new tiremarks - surveillance

mitochondrial DNA

from "powerhouse" of cell where the production of adenosine triphosphate (ATP) occurs - inherited only from mother - used in hair analysis

why is it important to document investigative efforts that fail to produce evidence?

the defense attorneys can make claims that an inappropriate effort was made, or there were improper procedures

pattern diversity principle (own interpretation)

the different ways blood move determine the pattern at the end of the movement

terminal ballistics

the effect of the bullet on a human target, determined by the forensic pathologist - range of wound - entrance or exit wound - path of travel and through which organs and structures - types of injuries (penetrating, perforating, tangential, grazing)

Scientific Murder Investigation, Luke May (1933)

the investigator must "develop other facts, correlating and interlocking to make a whole from apparently disassociated separate units" - the true mark of the scientific investigator was one who could "work untiringly, obtaining facts upon which to predicate theories, changing his theories as the facts develop warrant"

chamber

the location of the firearm that holds the cartridge when fired

discipline of bloodstain pattern analysis considers...

the location, size, distribution, and other physical characteristics to derive information regarding the nature of the event that caused the pattern

algor mortis

the loss of body heat from the corpse - core temperature from the liver by the ME - from forehead using digital thermometer - axial temperature from the armpit - highly variable, with initial period following death in which it is static and an loss is effectively immeasurable - ambient conditions, body fat, and chronic medical conditions can affect heat los

Crimes and Clues, H. Rhodes (1933)

the object of crime scene evaluation was to decide specifically how the crime was committed and in what order the events occurred - believed in scientific method

EA Step 2: Establish event segments from the data available

identified through evaluation of forensic reports, photographs, sketches, and examination of physical evidence - can be defined by the presence of specific evidence, by the interrelationships of that evidence, or by scientific analysis of that evidence -analyst describes even segments as objectively as possible, eliminating inference and any subjective association - four basic questions

Zone of Possibility 3

impossible given the data - shooter is physically unable to align the barrel and produce the trajectory

plastic prints

impressions where a print has been deposited in a soft surface such as wax

supervison of controls

include defined levels of decided as a means specifying who can override a control message or allows procedure to go ahead in the place of the mask

roadmapping

incorporates three basic photographs in conjunction with a variety of placards and scales in order to accurately reflect the orientation, position, and detail of the various bloodstain patterns found in the scene - no photos are taken without at least one label in the photo

single bullet defect penetrates or perforates a solid substrate allowing rodding

indicated flight path is very accurate, particularly if there is a perforating defect and two centering guides can be used

blunt force injuries - abrasion

involve only the upper layer of skin and appear reddish brown with no significant tearing of the skin

adding machine paper

the paper is porous, and when in contact with the oils of a latent print, absorbs the oils - roll the paper with gentle pressure onto the area, and mark landmarks such as an arrow to the elbow, wrist, etc.; then tape the paper contact side up in a box, then brush with fine powder (Moonglo or Midnight Blu work best) - apply vertically on neck for manual strangulation

infrared (700-2,000nm)

just above the visible spectrum - IR reflective surface that is dark or multicolored in normal light will be visualized as white or light gray, increasing the contrast between the surface and soot, GSR, or blood - digital IR photography removed the internal camera filter, must use external barrier filter to prevent visible light - not predictable on what substrates will reflect (trial and error) - bruises will absorb the IR

reports - 5 factors pertinent to entry and exit

known and possible avenues of approach and departure

conchoidal fracture

lines on the edge of the fragment - side of the glass where conchoidal fractures lie at right angles is the rear of the glass, opposite the side of the force - side of the glass where the conchoidal fractures lie nearly parallel is the side where force was applied

sharp force injuries - incised wound

longer than it is deep - may be gaping or have a narrow slit, depending on Langer's lines - produce a lot of bleeding - primary mechanism of death is exsanguination - secondary mechanism of death is a compromise in the airway or blood supply to the brain, as when the throat is cut

whorls

make approx. 30% of prints - plain - central pocket - accidental

arches

make up approx. 5% of prints - plain - tented

loops

make up approx. 65% of prints - ulnar - radial - double

transitory effects

manifest themselves as often fleeting information or statuses of items - might fail to stand out to investigators - time and environment will destroy - heat of burning cigarette, ice in a glass, tire heat signature, warm engine

functional detail

manifest themselves in the operating condition of items in the scene - tells about what was possible - can disprove specific allegations - alarm clock set, weapon capable of being fired, doors locked, etc.

relational detail

manifest themselves through the investigator's ability to physically place items in the scene - establishing a correlation between various objects - presence of a void pattern

methodical crime scene search means...

marked by order and systemic habits or behavior

single or multiple defects (corresponding defects) in solid substrates and associated perforating or penetrating wound to victim

may be possible to place both the shooter and the victim in a distinct orientation at the moment of wounding

EA Step 6: Determine and final-order of the events

may demand refining the events or even recording the events

wheelbase

measurement from the center of the front hub to the rear hub - the distance between the two axles

track width

measurement of the width across the front or rear axle

voids

not true patterns, but a lack of staining in an otherwise continuous pattern, and appear most often in spatter events

fly spot patterns

occur as a result of fly activity in a scene, as they can track blood from a body of blood source and deposit it on surrounding walls and surfaces - they also regurgitate blood

compression marks

occurs when a tool is forced into soft material

non-spatter - saturation

occurs when blood is drawn into clothing, cloth, or permeable surfaces and rarely provide specific investigative information

spatter - impact - expiratory spatter

occurs when blood is present in an airway and the victim exhales, breaking up the blood into small droplets

alterations

often evident under ALS, since different writing instruments were likely used

physically altered bloodstain principle

once exposed, blood will react to environmental conditions in a predictable manner - may allow for estimation of the volume of blood or the minimum time since the blood was first exposed

blunt force injuries - lacerations

open, irregularly shaped trauma with tissue bridging between the sides of the defect - death generally results from lacerations to underlying internal organs

phenolphthalein

oxidation-reduction reaction of the chemicals that occur in the presence of heme - alcohol, phenolphthalein, hydrogen peroxide - immediate pink reaction

leuco-malachite green

oxidation-reduction reaction of the chemicals that occur in the presence of heme - immediate green reaction

external or exterior ballistics

path and trajectory of the bullet after leaving the barrel to its final impact, based primarily on evaluation of bullet defects at scene - types of defect (penetrating, perforating, ricochet or deflection, tengential) - verifying bullet defects (lead presence test, copper presence test, nitrite presences test) - shape of defect - direction of fire - zones of possibility

point-to-point search

path is cleared to focal point

non-spatter - smear

pattern created by the transfer of blood from one object onto another through some form of contact - can establish the sequence of the two events, and usually the direction of motion of the disturbance

spatter - drip trail

pattern of individual deposited on a surface, demonstrating movement of the dripping item from one point to another - technician may recognize the movement of individuals or objects in the scene

complex pattern

patterns that have multiple subpatterns making it up

hyperspectral photography

photographing beyond the normal human spectral range

decomposition

physical putrefaction of the tissue due to bacteria - blue-green discoloration in the lower right quadrant of the abdomen - swelling of tissue - protrusion of eyes or tongue - blackish blue discoloration of skin - marbling of blood vessels - purging and slippage of skin - high heat and humidity speeds the process, while the cold will delay it

Zone of Possibility 2

possible but awkward - trajectory path that is higher than the shooter's shoulders - not all trajectories will have a Zone 2

pharmacist's fold

prevents particles from escaping the fold - fold the two outer thirds of a paper inward but at a slight angle (one end slightly larger than the other) - fold in thirds again lengthwise - insert smaller end into the larger

wet-bench serology

prior to the identification of forensic DNA techniques, wet-bench serology was directed primarily at class differences in human blood - blood typing - variations in blood antigens - provided a description of the questioned blood sample, compared that sample with any known blood samples, and then offered a backdrop of statistical evidence

crystal violet for adhesive tape

produces blue or violet coloration - solution of 1.5g cyrstal violet powder in 100ml of ethyl alcohol, add 2ml per 100ml of water to create a working solution - tape is dipped or immersed in working solution for 30 seconds to one minute, then immediately held under cold running water - can be repeated if the contrast isn't enough

rifling refers to...

projections (lands) and depressions (grooves) in the barrel that gives the projectile its spin to increase distance and accuracy

systematic crime scene search means...

purposefully regular

radial fracture

radiate out from the central point in the fracture (wheel spokes) - use only radial fractures on first concentric fracture

impact patterns

radiating patterns made up of small circular and elliptical-shaped stains - created when blood is exposed to an external force or impulse at a point source, which breaks the blood mass into small droplets that radiate outward from that point

physical developer

reacts primarily with salts, fats, and waxes in a latent print - used only after all the previously mentioned processed are completed, as it will wash away all constituents of fingerprint residue - used on previously immersed or water-soaked porous evidence - requires the mixing of several solutions, silver, nitrate, with prewashes and rinses

fluorescein enhancement

reacts to heme in blood, but is observed only under ALS - 25ml water, 0.25g fluorescein, and 0.5g zinc, applied, then a light misting of 3% hydrogen peroxide - will fluoresce green when viewed with an ALS set between 455-485nm with yellow or orange filter

luminol enhancement

reacts with iron in blood and fluoresces - 100ml distilled water, 0.1g luminol, 0.7g sodium perborate, and0.5g sodium carbonate - color - duration - intensity

amido-black enhancement

reacts with protein in blood and results in a blue-black color - 500ml water, 20g 5-sulfosalicyclic acid, 3g amido-black, 3g sodium carbonate, 50ml formic acid, 50ml glacial acetic acid and 12.5ml Kodak Photo Flo 600 solution; dilute in 1L of distilled water - reaction takes between 30 seconds and 3 minutes - spray only on static surfaces at the scene, not evidence itself - not a fixative - can interfere with subsequent analysis

absolute chronology

related to timing aspects

reports - 4 environmental conditions

reports of weather or scene conditions and the impact on the scene

ejection patterns

require repetitive firing of a weapon from a known position

GSR pattern evaluations

requires the specific weapon and ammunition from the event

smoke and soot

result from the outflow of fire products - smoke associated with the hot-gas-layer pattern in confined spaces - smoke and burn plumes on surface indicated where a fire vented - help investigators to recognize the development and flow of the fire - the nature of the soot found deposited and the color of smoke and flame can provide clues regarding the nature of the fuel source burning

4R rule

ridge lines on radial fractures are at right angles to the rear

scanning electron microscope (SEM)

seeks unique fused particles that contain all three elements, as research indicates that the three elements will occur together in a single particle only in gunshot residues

relative chronology

sequencing of event segments in relation to each other

primary purpose of a crime scene sketch

serves as a graphic document to show the layout, orientation, and interrelationship of the scene and the evidence

Edward Oscar Heinrich ("Wizard of Berkeley")

set out a specific crime scene analysis methodology - analysis is "like a mosaic...every fact must be evaluated before it can be fit into the pattern. In that way every fact as it is develops and equated becomes a clue" - credited with "nothing just happens"

fire patterns

show the progress of the fire, demonstrate the nature of the fuels involved, and help to locate and isolate the actual origin of the fire - "visible and measurable physical effects" on the material in the scene (NFPA)

managed waste site

sites that have extensive records reflecting truck routes, truck identification, when specific trucks came in, where they dumped their load, and at what time they dumped

tangential bullet wounds

skims the surface producing several shallow wounds

zone search

small area and large area variations

wake effect

small fracture lines in the paint and//or metal itself, arcing out and away from the defect - extend out and opposite the direction of travel (like the wake of a boat) - may involved microfractures that can be enhanced by lightly powder the surface with contrasting powder

context

sought by correlating all of the evidence items to one another in an attempt to objectively describe the nature and order of the actions that entail the incident being investigated

non-spatter - blood into blood

spatter deposited into one another or into another liquid, resulting in an accumulation with secondary spatter randomly oriented around the margin - indicates a blood source was relatively stationary at that point

spatter - drip

spatter resulting from blood dripping from an individual or otherwise bloodied object - far less distinctive than drip trails

reports - 3 conditions of the scene

specific conditions that are pertinent to the investigation - cleanliness - level of disarray - descriptions of items of evidence, including transient evidence

Fundamentals of Criminal Investigation, Charles O'Hara (1956-1978)

spelled out methodology for analysis: - painstaking, comprehensive collection of data - arrangement and correlation of that data - definition of issues and investigative questions - development of a hypothesis along the lines of the available data and subsequent resolution of any hypotheses - testing of the hypothesis and elimination, when possible, of contradicting hypotheses - testing of the final hypothesis before acceptance

Hans Gross (1900)

spoke of the necessity of meticulous examination and collection of facts in order to "reconstruct the occurrence, build up by hard labor a theory fitted in and coordinated"

non-spatter - pools and flow

stains that accumulates slowly and always obeys gravity

standard anatomical position

standing, arms at side, palms facing outward

rigor mortis

stiffening of the muscles of the body - affects all muscles of the body at the same time, but is evident in the smaller ones first - can appear within two hours of death - typically greatest 8-12 hours after death - will begin to break down and disappear typically 24-28 hours after death - highly variable

strip and line search

strip = back and forth line = many people moving as a line

internal or interior ballistics

study and examination of the firearm itself, which also includes ejection patterns, GSR deposition, and other aspects - examines variety of class and individual characteristic marks that allow association and identification of bullets, casings, and weapons to one another

physical evidence

take the form of specific items found at the scene that are often collected for subsequent analysis and presentation - the evidence is what it is, the only error would be human interpretation of it

single penetrating bullet defect in a victim

terminal ballistics will define or at least suggest the general path of the bullet

EA Step 5: Audit the information

the process of looking beyond the obvious to try to validate or refute previous conditions - addition or consideration of some new piece of data or data relationships may allow the analyst to better define a sequence - only works when you actively try to prove yourself incorrect

SSVC - impact angle

the ratio between the length of the long and short axes of the resulting stain has an empirical relationship to the angle at which the droplet struck the target - the major axis of the bloodstain is equivalent to the hypotenuse of the triangle (line BC), and the minor axis is equivalent to the side opposite (line ab) - minor axis divided by the major axis = N - the inverse SIN of N is equal to the approximate impact angle

convergence point

the reverse vectors defined by the individual stains' directionality may converged in the scene, if the stains are related

projectile//bullet

the subunit of a cartridge that is expelled from the firearm under the pressure created by the burning propellant

cartridge case

the subunit of the cartridge that holds the primer and propellant

barrel

the tubular aspect of the firearm that directs the path of the projectile when fired

crime scene analysis

the use of scientific methods, physical evidence, deductive and inductive reasoning, and their interrelationships to gain explicit knowledge of the series of events that surround the commission of a crime (Association of Crime Scene Reconstruction)

pattern diversity principle (PDP)

the variations in combinations of blood volumes and forces acting on those volumes lead to recognizable class of patterns

shape of the defect

there is an empirical relationship between the shape of the bullet defect and the angle of the bullet's impact into the target - non-tumbling bullets generally leave circular to elliptical defects - leading edge of the defect will often have a clean margin, while the far edge will be rough - formula is the same as determining blood stain angle of impact (use only when trajectory rods cannot be used)

EA Step 1: Collect date, establish likely events

this information will speak to the existence of the event, even though the specifics of the event may still be lacking

unpredictable effects

those changes that occur in an unexpected or random fashion - might not be known or understood by investigators - subsequent observation often results in incorrect premises regarding when the crime occurred or other pertinent things - entry of police//fire//EMS

predictable effects

those changes to a scene or evidence that occur with some rhythm or regularity - provides a factual reference or an inference as to the actual time of the crime - entomology, rigor mortis, livor mortis

ejection studies

to determine the distance and direction the weapon will eject a casing when held in any given orientation

standard when pursuing a solution to crime

to the point of beyond a reasonable doubt - NOT probable cause

forensic pathologist

trained in additional skills, such as patterns of injuries, and speaks to both the cause and manner of death

class characteristics

traits of evidence that allow the item to be compared with a group - eliminates possibilities - prevents wasting time and money - size, color, patterns, etc.

individual characteristics

traits that allow the item to be included or excluded from having originated from a specific object or person - resulting from natural variation, damage, or wear - prints, bio, trace, firearms, tool marks, impressions, documents, chem

Hepatitis B virus (HBV)

transmitted primarily through direct and indirect contact with infected blood or body fluids - can survive in dried blood at room temp for up to one week - blood results in more infections than contact with other body fluids - symptoms = fever, nausea, malaise, jaundice, abdominal discomfort - less severe than HCV - on the rise, but preventative shots are available (OSHA requires to pay for inoculations for at-risk employees when requested)

Hepatitis A virus (HAV)

transmitted primarily through oral or fecal routes - symptoms = fever, nausea, malaise, jaundice, abdominal discomfort - less severe than HCV - on the rise, but preventative shots are available (OSHA requires to pay for inoculations for at-risk employees when requested)

crime scene search with blue light (485-530nm)

typical CSS filters employ a broad passband filter - w/ orange filter = biological fluids, fibers, and hairs to fluoresce - 525-530nm w/ orange filter = developing and visualizing prints w/ fluorescent powders

electrostatic dust lifter (ESDL)

used on floors, doors, walls, carpeting, clothing, and paper - various surfaces hold a positive charge, while the particles of dust deposited are negatively charged - the greater charge in the film attracts dust particles, transferring them from the weakly charged scene to the film, and the residual charge keeps the dust print in place - not effective on wet surfaces or impressions with a lot of dirt

event analysis: reconstructing entire events

uses scientific method as a backdrop while applying seven steps to identify (as fully as possible) the specific actions taken during an incident - concentrates on objective evidence (physical evidence) - end result will be compared in detail with testimonial evidence and investigative theories in an effort to determine whether they are valid statements or theories

char

usually result from direct flame involvement - can often demonstrate the relative time of burn for a surface, as well as indicate the direction of the fire movement

entry gunshot wounds

usually symmetrical with abrasion ring around outer aspect; soot, stippling - for close-up or contact wounds, usually a star-like (stellate) appearance to the skin with lacerations extending from the wound margins

bullet trajectory - angle of elevation

vertical = angle of the muzzle in relation to the target using a vertical reference line (movement up and down)

PDP - blood dispersed as a function of accelerated motion

when a volume of blood adheres to an object and the object is put into accelerated motion - cast-off = linear pattern of spatter - movement of object overcomes the force holding the blood to the object - either a small jet or individual droplets

PDP - blood that accumulates of flows on a surface

when a volume of blood collects or flows on a surface - flow - pool - saturations - patterns consisting of accumulations with generally irregular margins

PDP - static blood dispersed from a point source

when a volume of blood is present at a point source and the blood mass is exposed to an external impulse or force - radiating pattern of small circular and elliptical stains - small spatters radiate outward from the source - impact patterns, but also include blood dispersed by air such as expectorate

PDP - blood dispersed in a jet (streaming ejection)

when a volume of blood is released in a stream (referred to as a jet in fluid dynamics) - spurt = linear patterns, if the jet lands across a surface - gush = large accumulation, if jet is directed onto the same area - gushes produces spines and secondary spatter

forged writing

when analysts must compare a questioned document to known documents and attempts to identify the writer

PDP - blood dispersed as a function of secondary contact with a surface

when blood is deposited or displaced on a surface through some form of secondary contact - smear - wipe - swipe - pattern transfer - patterns of blood that demonstrate the interaction of the two surfaces - fluid is displaced on the original surface, transferred to a second surface, or any combination of the two

spatter - cast-off

when blood is flung from an object that is either in motion or which suddenly stops some motion - can assist the technician in understanding the orientation of the item being swung and occasionally in determining the minimum number of swings of the bloodied item

asphyxia

when the body is unable to take in oxygen or eliminate carbon dioxide - strangulation - smothering - choking - drowning - positional or mechanical - chemical

flashover

when the temperature in confined spaces reaches 1,100°F, nearly any ignitable surface in the room will begin burning

pinch point

where a bullet and metal first meet and a small island of paint survives

ejection port

where the expended casing is ejected from the chamber

fire "origin"

where the fire started

circle or spiral search

work from outside to inside with controlled speed and method - usually used inside

second perimeter boundary

working area, evidence holding area, staging point for equipment - physical buffer for unauthorized personnel

demarcations

"V" pattern caused by a flame rising on a wall

prints are identified and individualized based upon

"finding agreement of individual characteristics, with no unexplainable dissimilarities

The interpretive value of evidence is a function of what?

"the full meaning of evidence is a function of time and the item's surroundings" (Chisum and Rynearson) - the value of evidence is far more an issue of context than it is of mere content

four basic tenets of risk management

- being managing risk in the planning stages of an event (identify potential hazards and results in control measures that are more deliberate and thought our more thoroughly - accept no unnecessary risk (generally considered to be a willful engagement in a hazardous activity for which an obvious control measure exists - make risk management decisions at the right level (set logical and appropriate levels of authority based on a full consideration of the nature of the risk - accept risk only when the benefits outweigh the costs

bite marks

- best documented by a forensic dentist - ABFO scale with close-up photos - always swab for DNA - photograph each arch separately

full scope of on-scene hazards

- biohazards from body fluids - structural hazards from fire and explosion scenes - chemical or inhalation hazards found in fire scenes - inhalation, chemical, and fire hazards from processing methods - inhalation, chemical and explosive hazards associated with drug labs - biochemical hazards associated with terrorism

items with potential for DNA

- blood - bone - dandruff - hair when the root or scalp cells remain - feces - fingernails and scrapings - fingerprints - particulates - nasal and ear secretions - saliva - semen - sweat - urine (limited potential) - vaginal secretions

surface effects of fires

- bubbling on paint - clearn burn pattern - directional melting of glass

damage patterns

- charring - melting (in direction of the approaching heat source) - soot deposits - spalling patterns in concrete - "crazing" of glass - ghosting patterns - consideration of melting points

ranges of gun shot wounds

- close or hard contact = muzzle is in direct contact with skin - loose contact = muzzle is extremely close to the skin, but a gap is between the gun and skin - near contact - <5" from skin - intermediate - 5-40" from skin - indeterminate - no conclusion can be drawn

crime prevention

- community programs - youth programs - proactive control - neighborhood watches

problems with landfill scenes

- compacting of body and evidence - heat generated by the landfill (170°+) - various hazards (toxic, bio, broken sharps, metal, decomp)

regulating noncriminal conduct

- compliance with city ordinances - compliance with traffic regulations

duties of chemical analyst

- conduct examination of suspected drugs - identify some unknown substance at a scene - search for and isolate accelerant residues in fire scene evidence - isolate and identify toxins used in poisonings - evaluate blood or urine samples for drugs and alcohol

common findings of strangulation

- congestion of facial features - abrasions or contusions of the neck and surrounding skin - hemorrhage of the muscles in the neck with the possibility of damage - breakage of the hyoid bone

common findings of ligature strangulation

- congestion of the face - furrow mark produced by the ligature device, commonly below the voice box - hanging = inverted V at the point of suspension - garroting = relatively even height around the neck - autoerotic = generally considered accidental, scene indicators include presence of escape mechanism, padded ligature, and presence of female clothing

issues with using trajectory rods

- considering the distance between the weapon and the impact - ensuring that the bullet is not tumbling - objectively demonstrating the evidence trajectory

post-processing biohazard exposures

- contamination of crime scene equipment and clothing - inadvertently bring soiled items home

two venues of analysis

- crime lab = physical evidence - crime scene analysis = evaluating all of the information available

What are the five objectives of preventing crime and disorder and protecting the life and liberty of their fellow citizens?

- crime prevention - crime repression - regulating noncriminal conduct - provision of services - protection of personal liberty

What two of the five main objectives of policing are related to crime scene investigation?

- crime repression = if unable to prevent crime, they must investigate the crime full and impartially and, if possible, identify those whom are responsible and apprehend them - protection of personal liberty = police must control their own behavior to ensure that their methods and practices abide by the Constitution and the law

adhesive size of tape

- crystal violet, alcohol, and water - sticky-side powders - can freeze tape in an attempt to unstick it from itself

non-porous rough surfaces methods

- cyanoacrylate (on scene to stabilize) - powder - silicone-based casting material - textured surface lifting tape or material

rough polystyrene surfaces

- cyanoacrylate fuming - SPR

non-porous smooth surfaces methods

- cyanoacrylate fuming (on scene to stabilize) - powders (fluorescent for contrast) - small particle reagent - silver nitrate (some plastics) - iodine (fresh prints, not on metal)

scientific method

- defining the problem or question to be resolved - collecting data to resolve the problem - developing a hypothesis - classifying and organizing data and establishing predictions - testing the predictions of the hypothesis - defining a conclusion

three attributes reports should have

- detailed - accurate - understandable

trajectory analysis documentation

- each defect must be distinguishable from another in photos through roadmapping - corresponding defects that perforate doors and other object should be given an alphanumeric designation - square camera, oblique lighting - measuring X, Y, and Z positions - sketches should clearly distinguish perforating defects from deflections or penetrations - terminal defects that hold bullets or fragments should be marked, and the nature of the recovered bullet should be detailed in notes

direction of fire

- entry holes - exit holes - in metal - in glass - trajectory rods and lasers

reports - 9 additional examinations

- evident fire patterns and fire flow evaluations - trajectory analysis - blood stain pattern analysis - electrostatic lifter - specialized chemical enhancements

cons of Scan Station

- expensive - cannot handle scenes in crowded situations, such as with a lot of trees

cons of Total Station

- expensive - extensive learning curve - prone to a variety of errors - demands experienced operator - most significant error is movement or jostling of the machine once leveled - environmental issues

photographing luminol

- extend shutter duration 20-60seconds digital (3-5 minutes film) - tripod - towards end of exposure and prior to closing the shutter, direct a small flashlight onto surround surfaces in both a bounce-light and paint-with-light

the two classifications combined provide an overall risk assessment matrix

- extreme - high - medium - low

casings can be examined for...

- firing pin impressions - breech-bolt marks - ejector and extractor marks - can be compared to another

structure fires follow generally predictable patterns

- flows up and outward in three-dimensional pattern - can change direction, moving towards an oxygen source - will flow laterally across a horizontal obstruction - linear charring

tools for paints and polymers

- fluorescent microscopy - infrared spectrometry - gas chromatography - scanning electron microscope

how probably or likely it is that the hazard will occur

- frequent - likely - occasionally - seldom - unlikely

tools for chemical analysis

- gas chromatography mass spectrometry - ultraviolet and infrared spectrometry - microcrystalline test - pyrolysis

camera control issues - focus and depth of field

- greater DOF = overall and evidence-establishing - smaller DOF = close up - greater f-stop = smaller aperture = less light - lower f-stop = larger aperture = more light

non-spatter stains

- gush//splash (irregular margin) - blood into blood (irregular margin) - smear (irregular margin) - pattern transfer (regular margin) - flow and pool (regular margin) - saturation (regular margin)

five essential elements of crime scene sketch

- heading - diagram area - legend - title block - scale and direction notations

fire tetrahedron

- heat - fuel - oxygen - uninhibited chemical chain reaction between the three

provision of services

- helping stranded motorists - looking for lost children

specific conditions for prints

- human skin - adhesive tapes - blood prints - rough polystryene - wet surfaces

landfill recovery methodology

- identify the appropriate cell or cells - backhoe and bulldozer - observation and rake teams - dump shovelful or trash and spread evenly - rake and observation teams - once done with one pile, it's bulldozed away - repeat - cadaver dogs

bullets can be examined for the purpose of...

- identifying a list of possible weapons that could have fired it based on the caliber and the number, size, and twist of the lands and grooves present - comparison between test bullets and questioned bullets using the smaller striations that lie parallel to the land and groove marks - comparison to each other - can NOT be compared to casings

debriefing the responding officers

- identifying specific boundaries and reasons why areas are included or excluded - general impressions of the officer regarding the nature of the crime and specific observations - if they discovered any items - how the crime came to the attention of the officer - specifics of what that information entailed - any changes that were made by officers, fire, EMS, etc. - specific entry//exit - things that were inadvertently touched - status of involved parties, and possibility of them having evidence on their person - any statements made to the officer - steps the officer took to secure the scene - crime scene logs

criteria for drip trail

- in-line distribution of spatter stains - consistent stain size range in the pattern, relative to any change in surface characteristics or decreasing volume available to produce the drip - the stains lead from one point to another - stains will typically range in size between 3 and 25mm

science of fingerprints is based on two fundamental principles

- individual - permanence

differentiating paint samples

- ingredients - chemical makeup - sequence of layering

three debriefings

- initial = upon investigator's arrival on scene - on-scene = what has been done and collected, etc. - formal = all primary parties 24hrs after

casting impressions in standing water

- place form around impression - building channeling tunnel if possible - slowly direct mixed dental stone into the form and allow it to settle to the bottom - can also sift dental stone powder slowly into the standing water, and when it becomes viscous, a form is added and the process is continued until a thorough mixtures is achieved

Adapted USACIDC Processing Model (US Army Criminal Investigation Command)

- initial notification - coordination, assessment, and team call-out - conduct initial observations - deal with the deceased - photograph the scene - document overall observations (eight set descriptive set) - sketch the scene - conduct first recheck - release the body - collect items of evidence - conduct second recheck - conduct third recheck - check beyond the scene - conduct an on-scene debriefing of the investigative team - release or secure the scene - process and package evidence - conduct a formal debriefing

three areas of study that make up ballistics

- internal//interior ballistics - terminal ballistics - external//exterior ballistics

porous surfaces methods

- iodine - ninhydrin - 1, 8-diazfluoren - indanedion - physical developer - hyperspectral photography

recurring problems in crime scene photography

- lack of understanding or practice with camera equipment - failure to understand and capture what is intended - significant comprehension problems include identification, orientation, confusion, and incomplete documentation

bullet and bullet fragment examination

- layering of trace evidence, indicative of sequence of targets struck - damage to the projectile, indicative of the type of target the bullet struck - deformation of the projectile, indicative of a deflection along its flight path and the angle of deflection

three ways to verify that a defect is associated with a bullet impact

- lead test (sodium rhodizionate or Plumbtesmo) - copper test (dithio oximide DTO or Cuperotesmo) - nitrite test (nitrite compound or modified Greiss test)

processing human skin for prints

- magnetic powder and brush - iodine fuming with silver plates (only on deceased) - adding machine paper process - cyanoacrylate fuming, but moisture will negatively affect it (only on deceased)

five observational conditions inconsistent with life

- massive head trauma - decapitation - major evisceration - massive blood loss - evident decomposition

things to take into consideration when processing a scene for prints

- methods for lifting prints on scene represent only a fraction of the techniques available for recovering fingerprint evidence - fingerprints are quite enduring - there is no way to accurately predict when fingerprints will be deposited

exit bullet holes

- more irregular - coning effect - material pushed away from the defect

factors to consider regarding the area to be searched

- nature of the ground being searched - lighting conditions - on-scene environmental conditions - size(s) of the item(s) being searched for

potential effects of the hazard to both personnel and the mission

- negligible - moderate - critical - catastrophic

GSR methods of analysis

- nitrate test on items to identify possible GSRs on scene - Atomic absorption analysis - neutron activation - scanning electron microscope

common issues with close-up photos

- not filling the frame - not having the sensor perpendicular to the object - not taking photos both with and without scales - not taking at least one close-up of each side of an item

four key elements of crime scene documentation

- notes - photos//video - sketches - reports

criteria for drip

- one or more spatter stains - parent stains have a generally large diameter (typically 3-25mm) - randomly oriented on a surface

mistakes when using video at scenes

- panning or zooming too quickly - abrupt movements - not being methodical - not using additional lighting - no realizing audio is on - not being confident if providing narration

porous surfaces

- paper - cardboard - untreated wood - currency - checks - packaging material

underlying principles that guide behavior of the bloodstain pattern analyst

- pattern diversity principle - principle of stain shape and vector correlation - physical altered blood stain (PAB principle)

casting standard impressions

- photograph first - remove large loose debris - in loose soil, powder, or sand, use fixative spray - place form around impression if needed - mix dental stone with water to get a pancake batter-like compound - gently pour into impression until covered to a depth of at least 1/2 inch

if computer is off

- photograph the condition and all peripheral connections - disconnect power - annotate all connections and cables using labels so it can be reconnected - remove cables and package - place clean or unformatted media into any open CD drives and tape shut - secure and protect system components from rough handling or magnetic energy - unless it is clearly unnecessary, seize all peripherals such as printers, scanners, and other external devices

good quality photos for any pursuit requires...

- physical control of the camera - proper use of the camera's controls - proper composition

direction of fire in metal surfaces

- pinch point - wake effect - lead or copper splash in rhodizonate or DTO tests, radiating away from the defect in the direction the bullet was traveling

electrostatic dust lifter process

- search area with oblique lighting - prepare Mylar film and place on area with dark side down as flat as possible - ensure it is grounded - apply charge by touching wand to film for a few seconds (charge will dissipate in 5-10sec) - roll over film to remove access air bubbles - remove film and examine briefly with oblique lighting - containerize as soon as possible, as the film will retain a charge and can attract ambient dust (in box with shiny side up; static-free bags; call roll it, but not lightly)

pros of Scan Station

- set-up to completion of one scan location is approx. 20 minutes - captures data that would not or could not be captured through manual mechanisms, which allows the technician to revisit the virtual scene and obtain measurements of objects that were not initially considered important - data can be viewed in a number of different fashions - produces very effect demonstrative aids for the courtroom

camera control issues - physical

- shutter speed 1/60th or less = focal length 50mm and under - shutter speed 1/250th = focal length more than 100mm

factors that affect team composition

- single or multiple scenes - order of activity involving specialty examination needs - available resources (equipment or personnel) - physical size of scene

tool mark class characteristics

- size - shape - mold variations - extrusion marks - milling marks

small area zone search

- small confined spaces not easily searched by patterned movement - vehicle searches - prevents searchers from indiscriminately moving from one point of interest to another

large zone seach

- split larger area into grids - allows for more effective command and control - provides a more thorough search and easier identification of locations

spatter stains

- spurt (linear) - cast-off (linear) - drip trail (linear) - impact (non-linear) - drip (non-linear)

hair and fiber evidence collection

- strips of tape, gently applied to surface until no longer tacky, then place on transparent plastic - repeat until entire surface is covered

issues associated with investigating fire scenes

- structural stability - exposed metal, nails, and other objects - inhalation hazards - lighting, or lack of - charring, and will absorb flash

minimum requirements for photo log

- subject of photo - exposure number - basic administrative data (case number, date, time, photographer, camera used, scene, etc.)

four principles of crime scene reconstruction

- superposition - continuity - chronology - relationship

fire scenes rules of thumb

- the area exhibiting the most damage was exposed to the fire for the longest time, and therefore is more likely to contain the point of origin - seek out any indication of low burn

general rules regarding the relationship of a bloodstain's shape and impact angle

- the smaller the angle of impact, the more elliptical the stain - the larger the angle of impact, the more round the stain will be

if computer is on

- try to determine if a destructive program is operating (common for pedophiles, hackers, and computer-savvy drug dealers) - if any indication of significant disk activity with no underlying cause, disconnect power immediately - if not a concern, photograph the screen and document the nature of any programs running on the system - then do same as if computer is off

casting snow prints

- use dental stone, but let is cool in the snow to ambient temperature before pouring in the impression, so the exothermic reaction doesn't melt the impression - can spray the impression with Snow Print Wax - can "dry cast" by lightly coating the impression with dry dental stone, then spraying with water, let dry for 5 minutes, then repeat until sufficient

camera control issues - lighting

- use fill flash for consistent light - off-set flash for close up to avoid overexposure - can diffuse or bounce light - ring lights provide 360° light coverage - paint with light - use flashlight for arson scenes

entry bullet holes

- usually looks like a cleanly punched hole - bullet wipe - inward beveled circumferential ring around defect

longwave ultraviolet light (365-415nm)

- view bloodstains, which will absorb light - effective presumptive test for bloodstains - provides sufficient contrast between red and violet objects and bloodstains - effective for visualizing semen, spittle, or saliva, which should fluoresce a lime green even without a filter

orange-red (570-700nm)

- viewing inks on items - questioned documents - w/ red filter = subcutaneous bruising, depending on the age of the bruise

non-porous rough surfaces

- vinyl - leather - textured countertops

EA Step 2: four basic questions that must be answered with regard to each object found

- what is it? - what function did it serve (not every object will be used as it was originally intended) - what interrelationships exist between the item and other items (physical, temporal, or spatial) - what does it tell us about time and sequence

reports - 1 introduction

- who worked the scene - where it was - time and date - short explanation of the reason why it was examined

three techniques for handling supervisors or politicians

-enforce the used of standard personal protective measures - enforce the use of scene entry logs - consider creating waling routes or observation points for authorized personnel

gelatin and other adhesive lifters

-gelatin lifters can be used on almost any surface, including textured and porous; but are more expensive and subject to damage in extreme heat - adhesive and rubber lifters are limited to use on nonporous smooth surfaces

criteria for spurts

-series of related spatter stains - large volume evident in the individual stains, demonstrated by flows from individual stains or a large volume in the overall pattern - lines of stains or overlapping stains deposited in "V", arc, or a serpentine pattern and/or - large elliptical stains

justice is the process by which...

..."each receives his due"

fingerprints develop in the human fetus at about...

...12 week gestation

DNA was first reported in...

...1868

structure of DNA discovered by...

...Watson and Crick in 1950s

at a minimum, the technician must understand and properly document bloodstain patterns so that...

...a subsequent analysis can be conducted

if roadmapping is done correctly...

...any bloodstain pattern analysis accomplished off-site through the documentation effort should achieve the same results as if the analyst had actually been on scene

an important aspect of scene documentation is...

...ensuring that the various elements of documentation complement and support each other

golden rule for crime scene investigation is...

...know who did what

identifies sperm through...

...testing for presence of acid phosphatase or by microscopic examination for sperm cells

identifies saliva through...

...testing for the presence of amylase or starches

the weakest link in forensic science lies with...

...the crime scene investigator

spatter - impact

a radiating pattern of small circular or elliptical- shaped stains created when blood is broken up at a source by some force - may result in defining an area of origin

trajectory rods and lasers

accuracy depends highly on case circumstances - use centering guides and non-warping metal rods - External Ballistics 4.0 -

Crime Scene Investigation...Henry Lee's Crime Scene Handbook, Dr. Henry Lee

advocated the use of scientific method as the specific means utilized in reconstruction - data collection - conjecture - hypothesis formation - hypothesis testing - theory formulation

triangulation or rectangular coordinates on a grid

after the grid is made, items can be fixed using triangular or rectangular coordinates to a grid corner - use the Cartesian method, preferably - check square of grid using 3-4-5 rule = from a point three units from the grid corner on one axis, to a point four units from the same corner on the adjacent axis, the distances between the two points is five units (pythagorean theorem) - triangular = large-scale scenes with multiple teams and not significant landmarks - rectangular = small-scale scenes such as gravesites

testing for lead presence in bullet defects

aka sodium rhodizionate or Plumbtesmo - filter paper twice the size of the defect is moistened with 15% solution of glacial acetic acid, then pressed against defect - if metallic lead is present, it will cause the lead to transfer to the paper with no visible change - paper is sprayed with a working solution of sodium rhodizonate - positive reaction = bright scarlet - final confirmatory test = spray the paper with 5% solution of hydrochloric acid, which will turn it a blue-violet

multiple bullet wound defects in the body or clothing caused by a single projectile

alignment will at least define the orientation of the associated body parts at the moment of wounding

Polymerase Chain Reaction (PCR)

allowed the scientist to copy the DNA structure in small samples, quantities too small to allow for RFLP techniques - but...it was uncommon to have statistical results as low as those found in the old-style serology

RUVIS (Reflective Ultraviolet Imaging Systsms)

allows the visualization of latent prints before dusting or development on most nonporous surfaces, as well as visualization of other evidence such as latent footwear patterns - effective at enhancing cyano prints - clear filters used for photographing background patterns or viewing bloodstain patterns in a luminol reaction - mirrored filter is used for undeveloped prints - can be operated in any lighting conditions - uses only UV/C (254nm) light - primary issue is adjusting the angle of incidence for the light source - can damage DNA, and cause burns similar to sunburns

event analysis

an in-depth crime scene reconstruction that employs scientific method to evaluate the physical evidence known to the analyst (Gardner & Bevel)

non-spatter - gush//splash

an irregular pattern created when blood is ejected in volume - classified as non-spatter because their primary stains are large-volume accumulations with irregular margins, although some form from the same process as a spurt

criteria for smear

an irregular shaped stain demonstrating any of the following - a contiguous boundary - a feathered boundary - striations in the body of the stain - diminished volume of blood across the body of the stain - evident displacement of blood

Hepatitis C virus (HCV)

attacks the liver and leads to serious liver problems and death - NO preventative treatments - similar exposure routes as HBV

human immunodeficiency virus (HIV)

attacks white blood cells known as CD4 T-cells, reducing the ability of the host to fight off other infections - if the CD4 cell count falls below a certain level, the individual is considered to have acquired immune deficiency syndrome (AIDS) - transmitted primarily through contact with blood, semen, and vaginal secretions - can remain active for up to 3-5 days in a dried form, and longer when wet - risk appears relatively low for crime scene exposure

Total Station

automated surveying system that use methods similar to polar coordinates, combining transits, lasers, and computer technology to create accurate scaled drawings - sighting device is aimed either at a laser reflector or at a specific point in the scene using reflector-less systems - measures horizontal angle, vertical angle, and slope distance

Criminal Investigation: A Method of Reconstructing the Past, James W. Osterburg

believed that physical evidence was the primary source of data from which any reconstruction should develop

baseline coordinates

best suited for exterior scenes without evidence landmarks - set datum point by triangulating it to a set of nearby landmarks, then extend baseline in a compass direction in a straight line using a non-stretch tape measure - measure distance from each item at a right angle to the baseline, and also record where on the baseline it fell

triangulation on a baseline

best used for exterior scenes where the field of evidence is not too widely scattered, but where there are no adequate landmarks - both ends of a baseline are triangulated to surrounding landmarks, then reference points are marked at recurring points along the baseline (i.e.: every 5 feet) - items are triangulated to reference points

asphyxia - choking

blockage of the airway itself - foreign body will be found in the trachea - little, if any, physical indicators will be found on the scene

asphyxia - smothering

blockage of the airway itself - mouth and nose are covered - little, if any, physical indicators will be present

theory of bloodstain pattern analysis

blood as a fluid (a complex fluid) responds to variations of internal and external forces in a predictable fashion

Evidence and Crime Scene Reconstruction, Chisum and Rynearson

method emphasized the importance of contextual information, a concept grounded in the belief that time and surroundings were a significant source of objective data - suggested the use of logic pathways and a "storyboard" approach, in which specific events were mapped out once they were identified and then sequenced within the whole reconstruction - criticism = continued to incorporate subjective aspects of the investigation, such as intent and motive, into the early stages of the reconstruction process

testing for nitrite compound in bullet defects

modified Greiss test - used on surfaces believed to have GSR from the muzzle being close to the surface when it was fired

indented

most often recovered using electrostatic detection apparatus (ESDA)

Zone of Possibility 1

most probable - some point along the trajectory at or lower than the shooter's shoulder height

thermal injuries

muscles and tendons often shrink, which causes appendages and neck to bend - pugilistic stance = fetal position, head down, legs drawn up, arms as if in a fighting stance - can result in broken bones, large tearing and lacerations to the external skin, and skull fractures

distance determination

must be made using the same weapon with the same ammunition thought to be used in the shooting - different ammunition may have different types of gunpowder with different flight characteristics or different amounts of gunpowder

fire starts with endothermic reaction (pyrolysis)

the breaking down of the fuel source into gas and vapors from heat

asphyxia - chemical

the chemicals replace the oxygen in the bloodstream - carbon monoxide = often a distinctive cherry red coloration of the skin - carbon dioxide = often a red or pink skin tone - no absolute psychical patterns of injury

SSVC - directionality

the collapse of a free flight droplet on a surface produces a stain with a circular or elliptical shape - based on the collapse, the resulting long axis of the stain, and the creation of scallops, tails, and satellite stains that appear on or around the stain - convergence point - the tails will be on the side of the stain that the drop was moving in

Crime Investigation, Dr. Paul Kirk (1953)

the crime scene was the foundation of the criminal investigation and that field technicians (police officers and crime scene technicians) had to work side by side with scientists (forensic scientists at the lab) in order to unveil what physical evidence could describe about a given crime - Sam Shepard case

livor mortis

the settling of blood in the body due to gravity after blood circulation ends

principle of stain shape and vector correlation

the shape of certain bloodstains provide indicators as to the direction of deposition as well as to the spatial origin of the blood - directionality - impact angle

serial number restoration

the stamping of the serial number during manufacturing results in molecular disruption and change the metal beneath the actual serial number mark - examiner will grind down and polish the area - then apply acid, which interacts with the stamped and surrounding metal