Download What is Forensic Science? - Forensic science is science applied to

What is Forensic Science?
- Forensic science is science applied to ________ problems.
- “Forensic” comes from the Latin language meaning
“having to do with argumentation and debating”
- Forensics and Forensic science ARE NOT THE SAME
THING.
What is criminalistics?
- Refers to activities of a full-service forensic science
laboratory (CSI type of work)
- Examples: DNA fingerprinting, fingerprints, protein
analysis, hair and fiber analysis, etc.
Corpus Delicti- Elements of a Crime
- all elements of a crime must be proven “beyond a
reasonable doubt”
- must be able to gain a conviction
- Example: Illegal drug possession case:
The crime lab must establish the white powder is cocaine, or
that the funny-looking cigarettes contain Cannabis sativa
(marijuana)
Example: Drunk driving case:
The crime lab must prove that the person charges had a blood
alcohol level above the legal limit.
** No elements of a crime can be worth any conviction
unless you persuade a judge, jury or administrative officer**
Trier of fact- The person or persons charged with critically
evaluating the facts as presented in a legal case.
i.e. the judge or jury
Forensic Science Databases- have been developed to help
forensic science during the investigative phase.
Examples:
- (CODIS) The Combined DNA Indexing System. “Bank”
that stores DNA profiles of convicted offenders and
suspects in cases
- (AFIS) Automated Fingerprint Identification System.
Contains many known fingerprints and fingerprints not
yet identified.
- (NIBIN) National Integrated Ballistic Identification
Network. Contains image data from bullets and
cartridge cases from known weapons seized from solved
and unsolved cases.
** All databases are referred to as “forensic files.” **
Brief History of Forensic Science
- First traces can be seen in China in 1250 AD
- Accepted origin is believed to be between 1800 and
1850….. this is when the formal scientific approach
was developing
- New foundations in chemistry and medicine
- Microscopes became available
- Doctors carefully dissected bodies to better
understand human anatomy
Matthew Orfila- (1787- 1853) French scientist that was called
“The father of Forensic Toxicology”
Hans Gross- law professor; in 1893 published the first official
book called Handbuch fur Untersuchungsrichter (translated to
Criminal Investigation: Application of Scientific Techniques)
 Gross is given credit for the word criminalistics
Alphonse Bertillon - 1890’s; developed a method for criminal
identification for the Paris police agencies that was based on
body measurements.
 Dead and arrested people had their measurements kept on
file (similar to today)
__________________________________________
Early 1900’s the United States was the leader in forensic
science.
1923- oldest forensic laboratory was created in Los Angeles by
August Vollmer.
1932- Federal Bureau of Investigators (lead by J. Edgar
Hoover) organized a national lab that offered forensic services
to all law enforcement agencies.
 World’s largest forensic lab
 Performs over 1 million tests each year
1981- FBI started the “Forensic Science Research and Training
Center”
 Lab was dedicated to develop new and reliable scientific
methods that can be applied to forensic science
The Organization of a Crime Laboratory
Today, there are 320 public crime laboratories operating in the
United States (3x the number versus 1966)
 DNA crime labs have been increased over the last 20
years. Why?
The FBI operates:
Drug Enforcement Administration: (Department of Justice)
(DEA) – DEA is responsible for the analysis of drugs seized in
violations of the law.
Bureau of Alcohol, Tobacco, and Firearms (Department of
Treasury) - is responsible for analyzing beverages and
documents relating to tax enforcement as well as examining
weapons, explosives and related evidence.
Services of the Crime Lab
- not all crime labs are considered “full service”.
- A “full service” crime lab has the following
laboratories.
Physical Science Unit- applies principles of chemistry, physics
and geology to compare crime scene evidence.
Subunits:
 Drug Identification
 Mineral Analysis
 Trace Evidence
Biology Unit- staffed with biologists and biochemists that
apply their knowledge to DNA profiling of dried bloodstains,
body fluids, hair, fibers and botanical materials.
Firearms Unit- Examination of firearms,
discharged bullets, cartridge cases, shotgun
shells. “GSR” and “tool-marks” on clothes is
also in the Firearms Unit jurisdiction.
Document Examination Unit- handwriting and
typewriting on questioned documents, paper and
ink examination, erasures and burned/charred
documents.
Photography Unit- complete photographic
laboratory that uses specialized photographic techniques such
as digital imaging, infrared, ultraviolet, X-ray photography to
make information visible to the naked eye. This unit prepares
photos for courtroom presentations.
Toxicology Unit- Body fluids and organs are examined to
determine the presence or absence of drugs and poisons.
Latent Fingerprint Unit- responsible for
processing and examining evidence for latent
fingerprints.
Polygraph Unit- responsible for performing
polygraph (lie detector) tests; responsible for
techniques of criminal investigations and interrogation.
Voiceprint Analysis Unit- responsible for telephoned threats
and tape-recorded messages. This unit can transform human
speech into a “voiceprint” which is then used in the court of
law.
 Every person has 2 unique parts of their speech
1. Voice uniqueness lies in the sizes of a person’ nose,
vocal cavity, throat and individual vocal chords.
2. The effect of the mouth, lips, teeth, palate and jaw
muscles make each person’s speech very unique.
Evidence Collection Unit- responsible for dispatching specially
trained personnel to the crime scene to collect and preserve
evidence; used in the court of law.
Example: Stokes, Brown, Grissom and Willows on CSI
http://www.csiwiki.cbs.com/page/CSI+Characters/diff/58,59?t
=anon
The Functions of the Forensic Scientist
1. Apply the principles and techniques of physical and
natural science to analyze evidence.
2. Must understand the demands and constraints of the legal
system.
3. Bear witness in a courtroom testimony. The forensic
scientist often takes the role of expert witness- individual
whom the court sees as very knowledgeable relevant to
the trial.
4. Responsible for Recognition, Collection and Preservation
of Physical Evidence (often times the patrol man is
responsible for evidence collection!!)
Other Forensic Science Services
Forensic Pathology- involves the investigation of sudden,
unnatural, unexplained or violent deaths.
Often a forensic pathologist is a medical doctor (coroner or
examiner).
Main goal of the pathologist is to
perform an autopsy- a medical
dissection and examination of a body in
order to determine the cause of death.
Questions the pathologist must ask:
 Who is the victim?
 What injuries are present?
 When did the injuries occur?
Why and how were the injuries produced?
5 categories of death:
 Natural
 Homicide
 Suicide
 Accident
 Undetermined
The pathologist uses clues such as rigor mortis- (stiffening
of body parts after death) and liver mortis- (collection of
blood in areas of the body next to the ground) to
determine the earliest possible time of death.
What causes liver mortis?
Algor mortis- condition where the body continually cools
after death until it reaches ambient (environmental)
temperature.
Body temperature loss: about one hour after death the
body loses 1 to 1.5 degrees Fahrenheit per hour until the
body reaches ambient temperature.
Forensic pathologists used potassium (K) levels in the
ocular fluid (eye fluid) to determine time of death.
After death eye cells release Potassium ions into the eye
fluid.
** Food in the stomach can also be used to determine the
time of the last meal, thus approximate time of death.
Forensic Anthropology- involves the investigation and
identification of human skeletal remains. The Forensic
anthropologist also is responsible for making facial
reconstructions.
 Human bones are very resistant to
breakdown
 Study of bones may
reveal their origin, sex, age,
race and skeletal injury
Example: a female’s pelvis will differ from that of a
male because of childbirth capabilities.
Forensic Entomologist- responsible for the study of insects and
their relation to criminal investigations.
Ex: When a person dies their decomposing body attracts insects
that lay their larvae (eggs) inside orifices of the body.
 The entomologist can identify what species of insects are
present and the approximate time since death of the victim.
Example Insect Life-Cycle:
Blow Fly Life Cycle:
Forensic Psychiatry- responsible for the relationship between
human behavior and legal trials.
 Determine whether people are competent
to make decisions about
-Preparing wills
-Settling property
-Refusing Medical
Treatment
-Stand Trial
Forensic Odontology- responsible for information for the
identification of victims when the body is left in an unrecognizable state.
Forensic Odontologist’s main focus is
teeth.
**Teeth are the hardest substance within the body**
**Teeth are very resistant because of their enamel**
 Teeth will outlast tissues and organs and decompose very
slowly.
Forensic Odontologist’s will use dental
records and bite marks to identify a
specific person.
Forensic Engineering- responsible for failure analysis, accident
reconstruction, and causes and origins of fires or explosions.
Forensic Engineers answer the following questions:
 How did an accident or structural failure occur?
 Were the parties involved responsible?
 If so, how were they responsible?
__________________________________________