INTRO TO FORENSIC SCIENCE
Chain of custody
A list of all persons who come into possession of an item of evidence
Area of convergence
A two-dimensional plane from which the drops in an impact pattern originated
Which of the following is the best explanation for the increased number or growth in the number of crime labs in the United States?
All of the reasons listed have led to the growth in the crime lab in the U.S.
What contributor to forensic science is known as the father of criminal identification?
Alphonse Bertillon
Back spatter
Also known as blow-back spatter, is projected backward from the source
Forensic science is
An umbrella term that encompasses many different professions that use their skills to assist law enforcement in conducting investigations
Broadest definition of forensic science
Application of science to criminal and civil laws. "The application of science to law"
At the crime scene, the string method is used to find the _____ of an impact spatter pattern.
Area of origin
What individual is noted for the creation of the oldest forensic lab in the United States in 1923?
August Vollmer
What contributor to forensic science refined the techniques involved in determining whether a particular firearm was used in a crime or incident by comparing the physical evidence found at a crime scene with a round that was test-fired from the same firearm through the use of the comparison microscope?
Calvin Goddard
Arterial spray spatter
Caused by an injury to the heart or a main artery and the pressure of the continuing pumping
A list of all of the people who came into possession of an item of evidence from a crime scene is known as what? This is very important because it plays a vital role in court, in determining the authenticity and integrity of the evidence, and in determining if evidence will be considered admissible or not.
Chain of custody form
3 major avenues used to assist enforcement
Confessions, witness testimony, and physical evidence (lacks bias/error)
Expirated blood pattern
Created by blood that is expelled from the mouth or nose from an internal injury. Usually high velocity spatter due to being under pressure
Finished sketch
Created from the information in rough sketch, but is drawn to scale with care and concern for appearance
Cast off spatter
Created when a blood-covered object flings blood in an arc onto surface. Usually produced by fists or between blows
Void pattern
Created when an object blocks the deposition of blood spatter onto a target surface or object and the spatter is deposited onto the object or person instead
Contact/transfer pattern
Created when an object with blood on it touches one that does not have blood on it
Locard exchange theory
Cross transfer of evidence occurs
Leone Lattes
Developed procedure to determine blood type from dried bloodstains and used it as a way to id an individual
Albert Osborn
Document examination
Which of the following is considered a basic service provided by a full-service crime lab?
Document examination unit
Medium velocity spatter
Drop with diameters from 1-4 mm with an applied force of 5 to 25 ft/sec
Low velocity spatter
Drops with diameters of 4 mm or more normally produced by an applied force of up to 5 ft/sec.
High velocity spatter
Drops with diameters of less than 1 mm; applied force of 100 ft/sec or faster
Physical evidence
Encompasses any and all objects that can establish that a crime has or has not been committed or can provide a link between a crime and its victim or a crime and its perpetrator
Class Characteristics
Evidence associated only with a group is said to have class characteristics
Correct physical evidence collection procedure.
Evidence from an arson crime scene, especially that with fumes, should be packaged separately in airtight metal cans
Individual characteristics
Evidence that can be associated with a common source with an extremely high degree of probability -fingerprints-
Forward spatter is more likely to be deposited on the object or person creating the impact
False
Identification is the process of ascertaining whether two or more objects have a common origin
False
In comparing the terms forensic science and criminalistics. Criminalistics is an umbrella term used to encompass all of the many professions that use their skills to aid law enforcement officials in conducting their investigations, whereas forensic science is a term used for describing all of the many services of a crime lab.
False
Most items of physical evidence retrieved at crime scenes can be linked definitively to a single person or object
False
NIBIN is the FBI's complete DNA database that became fully operational in 1998
False
The necessity for the forensic scientist to appear in court is based on the 5th amendment, but comes from the 1993 Supreme court case, Daubert v Merrell Dow Inc.
False
The oldest forensic lab in the United States is that of the FBI.
False
When conducting a search at a crime scene the search for physical evidence should be superficial and disorganized.
False
Francis Galton
Fingerprints
Role of probability
Frequency of occurrence of an event
What crime scene search pattern is noted for needing two investigators to conduct line searches, is known as being through, but that the boundaries must be well established in order to use it well?
Gird search pattern
What contributor to forensic science wrote in 1893 the first written work that described how the application of the many different scientific disciplines could be utilized in criminal investigation? Basically he detailed how each of these scientific disciplines could be of assistance to the criminal investigator.
Hans Gross
Which of the following is a national fingerprint and criminal history system maintained by the FBI and launched in 1999?
IAFIS
There are two processes that forensic scientists undertake when examining physical evidence. Determine that an explosive mixture contains dynamite is an example of what process
Identification
The amount of spatter from a blood droplet falling on a hard, non-porous surface is ________ that of a drop of blood of equal size, falling from the same distance, onto a softer, porous surface.
Less than
An impact pattern consisting of large separate drops with diameters of 5 millimeters is:
Low velocity spatter
General bloodstain features
May uncover - direction from which blood originated, the angle at which a blood droplet struck a surface
Calvin Goddard
Microscope and examine particular gun fired
Walter McCrone
Microscopy
Pools of blood
Occurs when blood collects in a level and undisturbed place. Blood that pools on an absorbent surface may be absorbed throughout the surface and diffuse, creating a pattern larger than the original pool
The presence of a cast-off pattern shows that there were more than ________ blow(s) delivered:
One
Spiral search pattern
One investigators searches in a spiral path from the center of the crime scene to the boundary (outward) or from the boundary of the crime scene to the center (inward)
Identification
Purpose the determination of the physical or chemical identity of a substance with as near absolute certainty as existing analytical techniques will permit
The database that includes more than 300 manufacturers of shoes with more than 8,000 different sole patterns is the:
SICAR
Rough or porous surfaces usually result in stains with
Satellite spatter
The use of what provides a safety net to ensure that the outcome of an investigation is not tainted by human emotion or compromised by distorting, belittling, or ignoring contrary evidence?
Scientific method
The duty of the first officer on scene or the first responding officer is to do what?
Secure and isolate the crime scene
Drop trail pattern
Series of drops that are separate from other patterns, formed by blood dripping off an object or injury
The Frye standard
Set guidelines for determining the admissibility of scientific evidence in court
Wheel/ray search pattern
Several investigators search in straight lines from the center to the boundary (outward) or from the boundary to the center (inward)
Which crime scene search pattern usually employs one person and involves working the scene from the center toward the boundary or from the boundary to the center of the crime scene? This type of pattern is not always beneficial because evidence can be missed.
Spiral search pattern
Comparison analysis
Subjects a suspect specimen and a standard/reference specimen to the same tests and examinations for the ultimate purpose of determining whether or not they have a common origin
Quadrant/zone search pattern
The crime scene is divided into smaller sections (zones). One or more investigators are assigned to search each zone
There are two types of sketches that are completed by the crime-scene investigator. Which sketch is drawn away from the crime scene and is a precise rendering of the crime scene and is usually drawn to scale. This is done with concern of aesthetic appearance, must reflect the information from earlier renderings, and is done with the aid of computer-aided drafting software?
The finished sketch
Effects of surface texture
The harder and less porous the surface, the less spatter results
Once the scene is secured and isolated and the lead investigator arrives, the lead investigator begins evaluating the crime scene. One of the first things done by the lead investigator is what?
The initial walk-thru of the crime scene
crime scene reconstruction
The method used to support a likely sequence of events at a crime scene by the observation and evaluation of physical evidence and statements made by individuals involved with the incident
Impact bloodstain spatter pattern
The most common type of bloodstain pattern
A standard/referred sample is physical evidence whose origin is known and can be compared to crime scene evidence to either make a match and determine who the suspect might be or to remove someone form consideration in a criminal investigation.
True
Crime labs in this country to large extent mirror the law enforcement structure that exists on the national, state and local levels. That means that crime labs are fragmented jurisdictionally.
True
Once the first responding officer responds to the scene of the crime and secures and isolates the scene. A log should be kept of the dates and times that all authorized and unauthorized people enter and exit the scene of the crime. Obviously those that are unauthorized should not gain access.
True
Ridge characteristics of fingerprints, random striating markings on bullets or ammunition, and irregular and random patterns in ties or footwear impressions all exhibit individual characteristics
True
The jury ultimately determines the significance of physical evidence in a trial
True
Line/Strip search pattern
One or two investigators start at the boundary of the crime scene and search in straight lines across to the other side of the crime scene
Skeletonization
Phenomenon that occurs when the edges of a stain dry to the surface. Usually happens within 50 seconds of deposition of the droplets
There are three ways to document the crime scene. Which one is utilized the least due to the cost of it?
Photography
3 methods to record crime scene
Photography (4 minimum ranges), sketches, and notes
The phenomenon known as the CSI effect is that which results from the dramatization of forensic science on tv and it causing the public to believe that every crime scene will yield forensic evidence and the unrealistic expectation that every criminal case should be bolstered and supported by forensic science.
True
The pointed end of a bloodstain always faces it's direction of travel
True
This contributor to forensic science, Albert S. Osborn, did not make nay specific technical contribution to forensic science, but instead he demonstrated how the many different scientific disciplines could be incorporated within the workable crime lab.
True
When measured or mixed with extreme precision, no two items- even those originating from the same source - we exactly alike
True
When using photography as a way to document the crime scene, csi prefer DLSR cameras. When using DLSR cameras, the number of pixels featured in the camera, the better the resolution.
True
The intersection of straight lines through the long axis of several individual bloodstains in an impact spatter pattern illustrates the ________ of the pattern.
area of convergence
Mathieu Orfila
father of forensic toxicology, first scientific treatise on detecting poisons and their effects on animals
Gunshot spatter
fine forward spatter from an exit wound and back spatter from an entrance wound. The gunshot produces only back spatter if the bullet doesn't exit the body
The likelihood of finding class physical evidence is ________ the likelihood of finding physical evidence with individual characteristics.
greater than
A bloodstain that impacts a surface at a low angle will have a ______ tail than one that impacts at a higher angle
longer
Flow patterns
made by drops or large amounts of blood flowing by the pull of gravity
Multiplying together the frequencies of independently occurring factors is called the:
product rule
Forward spatter
projected outward and away from the source
Angle of impact formula
sin A=(width of blood stain/length of blood stain)
Area of origin
the area in a three-dimensional space from which the blood was projected
A comparison analysis subjects a suspect specimen and a control specimen to the same tests and examinations for the ultimate purpose of determining:
whether or not they have a common origin
Two techniques used to document bloodstain patterns
1. Grid method - A grid of squares of known dimensions are set up over the entire pattern 2. Perimeter ruler - A rectangular border of rules is set up around each pattern and a smaller ruler next to each stain