INTRODUCTION
Chapter 1
What exactly is Forensic Science?
Forensic science applies the
knowledge and technology of science
to define and enforce laws.
The History of Forensics
• Mathieu Orfila (Spain)
“Father of Forensic Science”(1787-1853)
– Established the science of Forensic Toxicology, by
studying the effects of toxins on animals
• Alphonse Bertillon (France) (1853-1914)
– Developed the science of Anthropometry – a way of
taking extensive body measurements to identify
people. This technique of personal identification was
considered extremely accurate for 2 decades and
was eventually replaced by fingerprinting.
The NY State Bertillon Bureau in 1902
The first criminal identification card filed
by the New York State Bertillon Bureau.
More important people!
• Francis Galton (1822-1911)
– Proved the uniqueness of human fingerprints and
published a book called “Finger Prints”. Current
fingerprinting techniques are based on his research.
• Leone Lattes (1887-1954)
– Devised a technique to determine the blood group of
a dried bloodstain and applied the technique to
criminal investigations. (The ABO blood groups were
discovered by a Dr. Karl Landsteiner in 1901)
Dr. Karl Landsteiner in his laboratory, working on
blood samples
And more…
• Calvin Goddard (1891-1955)
– Used microscopy to determine if a bullet was fired
from a particular gun, and if that compares to the
suspect’s weapon and a crime scene bullet. Modern
firearms examiners still use his techniques.
• Albert S. Osborne (1858-1946)
– Published a book “Questioned Documents”, and was
responsible for the acceptance of documents as
scientific evidence by courts. Modern document
examiners still use his book as primary refernce.
A couple more…
• Walter C. McCrone (1916-2002)
– Did extensive work with microscopy to
examine forensic evidence.
• Hans Gross (1847-1915)
– The first person to write about marrying all
arms of science (Botany, antropology,
chemistry, physics, mineralogy, etc.) into one
unified investigative science: Forensics.
Last but not least…
• Edmond Locard (1877-1966)
– Established “Locard’s Exchange Principle”
which state that, whenever 2 objects come in
contact with each other, there will be an
exchange of materials between the two.
Therefore, when a criminal comes in contact
with an object or a person, a cross-transfer of
evidence occurs. So you can find something
of the criminal on the victim and vice versa.
• In 1932, thanks to J. Edgar Hoover, the director of the
FBI, launched a national lab that would offer forensic
services to the entire country’s law enforcement
agencies.
• Today, the FBI laboratory is the largest and most
reputable in the world.
Basic Services of a Full-Service
Crime Lab
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Physical Science Unit
Biology Unit
Firearms Unit
Document Examination
Photography Unit
Optional Services of a Full-Service
Crime Lab
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Toxicology Unit
Latent Fingerprint Unit
Polygraph Unit
Voiceprint Analysis Unit
Evidence-Collection Unit
Specialized Forensic Services
These are provided by specialized individuals, and
are not usually a part of a full-service crime lab.
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Forensic Pathology
Forensic Anthropology
Forensic Entomology
Forensic Psychiatry
Forensic Odontology
Forensic Engineering
1.Forensic Pathology
Investigates sudden, unnatural, unexplained, or violent
deaths. Questions a forensic pathologist must attempt to
answer:
Who is the victim?
What injuries are present?
When did the injuries occur?
What caused the injuries?
What was the time of death?
http://www.pathguy.com/TimeDead.htm
If a cause of death cannot be determined by external
observation of the body, then an Autopsy is required.
Autopsy
(means to see for oneself)
This a medical dissection of a body to
determine cause of death. Causes of
death can be classified as:
- Suicide
- Homicide
- Accident
- Natural causes
- Undetermined
Autopsy cont’d.
• The early stages of decomposition after death
involve:
– Rigor mortis: the muscles first relax, then stiffen. The
body becomes rigid. Rigor mortis occurs within 24 hours
after death and terminates within 36 hours.
– Livor mortis: Once the heart stops pumping, the blood
tends to pool in the parts of the body closest to the
ground due to gravity. The skin in these areas appear
purplish. However, skin that was restricted by belts, etc.
will not appear purplish. This can help determine if the
body was moved after death. Livor mortis begins
immediately after death and continues for up to 12 hours.
Rigor Mortis
Livor Mortis
Autopsy cont’d.
– Algor mortis: this is the conditions where the
body temperature cools and reaches the
ambient or room temperature. The location,
size of body, clothing, weather conditions, etc.
all play a role in algor mortis.
Generally speaking, beginning an hour after
death, the body loses heat at the rate of 1 or
1.5 degrees Fahrenheit per hour until body
reaches ambient temperature.
Pallor Mortis
Pallor mortis (paleness of
death) is a postmortem
paleness which happens
almost instantaneously (in
the 15–120 minutes after
the death) because of a
lack of capillary circulation
throughout the body.
Paleness develops so
rapidly after death that it
has little to no use in
determining the time of
death.
Other Autopsy Factors
• Potassium levels in vitreous humor of eye:
after death, cells of the inner eye release
potassium into the ocular fluid called
vitreous humor. Examining these levels
help determine time of death.
• Amount of food in stomach: can help
determine when last meal was eaten.
How long does food take in the GI tract?
50% of stomach contents emptied
Total emptying of the stomach
2.5 to 3 hours
4 to 5 hours
50% emptying of the small intestine
2.5 to 3 hours
Transit through the colon
30 to 40 hours
2. Forensic Anthropology
Deals with identification and examination of human
skeletal remains. Bones degrade at an incredibly
slow rate. They can tell:
- Sex
- Age
- Race / Origin
- Type of injury (cause of death?)
Forensic anthropologists are often needed to
identify victims of a mass disaster such as air
crashes, 9/11 WTC disaster, bombings, etc.
Ways to tell male pelvis from female:
spread of ilium: female more flared and cradle-like with anterior iliac spines farther apart vs. more
straight “up-and-down” in male
shape of hole in ischium: smaller and triangular in female vs. larger and rounded in male
angle across pubic symphysis: pubic arch: less than 90° (acute angle) and more sharply angled
in male, greater than 90° (obtuse angle) and more rounded in female
inner diameter and distance between ischia: larger in female--big enough for head of baby to
pass through
• Sometimes forensic anthropologists have to use
Facial Reconstruction artists to help identify the
remains.
http://www.crimelibrary.com/crimina
l_mind/forensics/art/5.html
3. Forensic Entomology
The study of insects and their relationship to a
criminal investigation. Can help determine time
of death.
After death, specific insects become inhabitants of
the corpse in a specific sequence. Blowflies are
usually the first to arrive. Knowing the life cycles
and studying the maggots can help determine
time of death. Ambient temperatures can play a
role in insect life cycles, so it can be tricky to rely
solely on this method.
A Blowfly and its maggots
4. Forensic Psychiatry
The relationship between
human behavior and legal
proceedings is examined.
Forensic psychiatry can help
determine:
- If a person is fit to stand
trial
- Suspect’s behavioral
profile
- Behavioral patterns of
criminals (Profiling)
Susan Smith
5. Forensic Odontology
Using teeth to identify remains.
Tooth enamel is the hardest
substance in the body and
usually the last to
decompose. So teeth can be
used (and old dental records
such as X-rays and casts) to
identify a body in an
unrecognizable condition.
Dental Impressions
and Casts
6. Forensic Engineering
This aspect of forensic science includes
accident reconstruction, causes and
origins of fires and explosions.
Body Mystery
• http://americasunknownchild.net/Medical.h
tml
• www.crimelibrary.com
THE END