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 Treasuryresponsible 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 Unitapplies 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 Unithandwriting 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 un-recognizable 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?
__________________________________________
***END OF CHAPTER 1 : INTRO TO
FORENSIC SCIENCE***