How does the textbook define forensic science?
application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system
Why is Orfila considered "the father of forensic toxicology?
teacher of medicine. published first scientific treatise on the detection of poisons and their effects on animals. Established toxicology as a legitimate scientific endeavor.
What was Francis Galton's principal contribution to forensic science?
First definitive study of fingerprints and developed methodology for classifying them for filing. Personal identification by fingerprints
How did Goddard advance the science of firearms examination?
Refined the techniques of examination by using comparison microscope, which became an indispensable tool of the modern firearm's examiner.
What is Locard's Exchange principle?
Whenever two objects come into contact with one another, there is exchange of materials between them. (cross-transfer of evidence)
What major advance in forensic science did the state of California undertake in 1972?
In 1972, California Department of Justice embarked on a plan to create a network of state-operated crime labs. Result = model system of integrated forensic labs consisting of regional and satellite facilities. Created California Association of Criminalist
List 3 reasons for the unparalleled growth of crime laboratories in the United States since the 1960s.
1. Supreme Court decisions in the 1960s were responsible for greater police emphasis on securing scientifically evaluated evidence
2. crime laboratories face overflow of drug specimens due to accelerated drug use
3. advent of DNA profiling
Describe how the structure of the US federal government has affected the organization of crime labs in the US.
Rapid growth. Lack of national and regional planning or coordination.
Variety of independent labs in the US, retain local control.
List three main reasons for the wide variation in total services offered by crime labs in different communities.
1. variation in local laws
2. different capabilities and functions of the organization to which a laboratory is attached
3. budgetary and staffing limitations
Describe the basic duties of the physical science unit and give three examples of the work performed by a physical science unit.
applies principles and techniques of chemistry, physics
What five units typically are found in full-service crime labs? List at least one function performed by each of these units.
1. physical science unit: Identifies & compares physical evidence. Incorporates the principles of: chemistry, Physics, geology
2. biology unit: applies investigates blood samples, body fluids, hair, and fiber samples
3. firearms unit: investigates dischar
List two optional units found in most crime labs and give at least one example of the type of work done by each.
1. Toxicology Unit: examines body fluids and organs for the presence
of drugs and poisons
2. Latent Fingerprint Unit: processes and examines evidence for latent fingerprints
3. Polygraph Unit: conducts polygraph or lie detector test
4. Voiceprint Analysis
List the main functions of the forensic scientist.
1. Analysis of Physical Evidence: Apply principles & techniques from physical and natural sciences to analyze evidence that may be recovered during a criminal investigation
2. Provide expert court testimony: an expert witness is an individual whom the cou
What important principle was established in the case of Frye V. US?
The Frye v. United States decision set guidelines
for determining the admissibility of scientific
evidence into the courtroom. To meet the Frye standard, the evidence in question must be "generally accepted" by the
scientific community
How did Daubert V. Merrell Dow Pharmaceuticals Inc. affect the admissability of scientific evidence in federal courts?
the U.S. Supreme Court asserted that the Frye
standard is not an absolute prerequisite to the
admissibility of scientific evidence. Trial judges were said to be ultimately responsible as
"gatekeepers" for: the admissibility and validity of scientific evid
How does the testimony of an expert witness differ from the testimony of a lay witness?
Lay witness must testify on events or observations that arise from personal knowledge. Testimony must be factual and with few exceptions, cannot contain personal opinions. Expert witnesses are called on to evaluate evidence when the court lacks expertise
List two ways in which a forensic odontologist can assist in criminal investigations.
Help when the body is left in an unrecognizable state. Teeth are the hardest substance in the body, and can help to identify victims based on dental records. Can also compare bite marks to tooth structure of suspect.
How does the textbook define physical evidence?
Any object that can establish that a crime has or has not been committed or can link a crime and its victim or its perpetrator
What is the first critical step in crime scene investigation?
Secure and Isolate the crime scene.
-Secure boundaries of crime scene with crime scene tape, ropes, or cones
-secured area should include: area where the crime took place, surrounding area where physical evidence may be located
-Once boundaries are secure
List the three methods of crime scene recording.
Photography, Sketches, Notes
What is the most important prerequisite for photographing a crime scene?
The most important prerequisite for
photographing a crime scene is for it to be in
unaltered condition.
What is a rough sketch and what must it accurately reflect?
Rough sketch: a draft representation of all essential information and measurements at a crime scene. This sketch is drawn at the crime scene. Must accurately depict dimensions of the scene and showing location of all objects having a bearing on the case
What information must be included in any notes taken at the
crime scene?
1. Identity of person who contacted investigator
2. Time of contact & arrival at crime scene
3. Preliminary case information
4. Personnel present on arrival and those being
contacted
Besides the crime scene itself, what locations must
investigators search?
All points of entry and exit, surrounding areas
What items from deceased victims must be collected and sent to a forensic laboratory?
Victim's clothing, fingernail scrapings, head and pubic hairs, blood for DNA typing, vaginal, anal, and oral swabs in sex-related crimes, recovered bullets from body, hand swabs from shooting victims for gunshot residue analysis
What is the main objective in collecting and packaging physical evidence?
To send to forensic labs to analyze the evidence as well as preventing the evidence from being altered/ prevents changes
What is the best way to maintain the integrity of evidence that is collected and submitted to the crime laboratory?
Evidence best maintains integrity when left in its original condition as found at the crime site.
Why is it important to package items of physical evidence in
separate containers?
packaging evidence separately prevents damage
through contact and prevents cross-contamination
Why should ordinary mailing envelopes not be used for
packaging physical evidence?
powder and fine particles will leak out of their corners
Describe a druggist fold and explain why it is a superior way to package small amounts of trace evidence.
Druggist fold - folding one end of paper over by one third, then folding the other end over that, and repeating the process from the other two sides, after folding he paper in this manner, tuck the outside two edges into each other to produce a closed con
Why should bloodstained evidence not be stored in airtight
containers? What is the best way to store such evidence?
if biological materials such as blood are stored in airtight containers, the accumulation of moisture may encourage the growth of mold, which can destroy their evidential value. In these instances, wrapping paper, manila envelopes, or paper bags are the r
Define chain of custody and explain why maintaining a proper chain of custody is important. What are the possible consequences of failing to maintain a proper chain of custody?
A list of all people who came into possession of an item of evidence. A proper chain of custody is important in order to guarantee that the evidence will withstand inquiries of what happened to it from the time of its finding to its presentation in court.
Why is it important to include a brief description of the case
history on an evidence submission form?
Allow the examiner to analyze the specimens in a logical sequence and make the proper comparisons. It will also facilitate the search for trace quantities of evidence
What two diseases have sensitized the law enforcement
community to the potential health hazards that can exist at crime scenes? Name three basic types of protective clothing that investigators use to guard against contamination by infectious materials at
AIDS and hepatitis B. Gloves, protective footwear, goggles, masks, coveralls, etc.
List four situations in which a warrantless search may be
justified.
1. the existence of emergency circumstances
2. the need to prevent the immediate loss or destruction of evidence
3. a search of a person and property within the immediate control of the person , provided it is made incident to a lawful arrest
4. a search
List six types of physical evidence derived from human or other animal sources that are commonly found at crime scenes.
� Blood, semen, &saliva
� Documents
� Drugs
� Explosives
� Fibers
� Fingerprints
� Firearms and ammunition
� Glass
� Hair
� Impressions
� Organs & fluids
� Paint
� Petroleum products
� Plastic bags
� Plastic, rubber, and other polymers
� Powder residues
�
List and define the two methods used by forensic scientists
when examining physical evidence.
1. Identification: physical or chemical identity of a substance, as near absolute certainty as existing analytical techniques will permit
2. Comparison analysis: Use same tests & examinations on suspect specimen and a standard/reference specimen, determin
To permit positive identification, testing procedures used by a forensic scientist must meet what two conditions?
Give characteristic results for specific standard materials and The number and type of test needed to identify a substance be sufficient to exclude all other substances.
Describe the two steps in the process of comparison. What
question does each step attempt to answer?
The first step in comparison is to choose specific combinations of properties from the suspect and the standard/reference specimen for comparison, The second step is for the forensic scientist to render a conclusion about whether the specimens come from t
Define individual and class characteristics
Individual - properties of evidence that can be attributed to a common source with an extremely high degree of certainty
Class - Properties of evidence that can be associated only with a group and never with a single source
Define the product rule and explain how it can be used to
determine whether two blood samples come from the same
source.
Product rule - multiplying together the frequencies of independently occurring genetic markets to obtain an overall frequency of occurrence for a genetic profile. If two specimens are being compared and they are both type A, and other blood factors are de
What is the greatest weakness of class evidence? List two
factors that contribute to this weakness.
Inability of examiner to assign exact or approximate values to comparisons of class evidence. Few statistical data.
What is the value of class evidence? Why is this important in
making a case to a jury?
Ability to corroborate events with data in a manner that is, as nearly as possible, free of human error and bias. Binds together an investigations findings
Why are some jurists wary of allowing unconditional use of
scientific evidence in court?
some jurists are wary about scientific evidence because juries often accord scientific
evidence greater weight than other evidence, tend to consider it more trustworthy, and
often view it with less skepticism. Without proper safeguards, the use of scienti
How can the extreme sensitivity of modern analytical
techniques hinder the process of comparing items of physical evidence?
When measured or examined with extreme precision, no two items - even those
originating from the same source - are exactly alike. Thus, using an analytic technique
that is too sensitive makes it impossible to meaningfully compare different items of
eviden
What are IAFIS and CODIS? Describe the purpose of each.
Integrated Automated Fingerprint Identification System: a national fingerprint and criminal history database maintained by the FBI. IAFIS allows criminal investigators to compare fingerprints at a crime scene to an index of 500 million known
prints
Combin