FORENSICS
FISHER SCIENCE EDUCATION
HEADLINE DISCOVERIIES
MAKING SCIENCE MATTER™
FORENSIC FARMING
B
ehind the employee parking lot of the
University of Tennessee medical center is an area surrounded by a six-foot, chainlink fence topped with razor wire and hidden
from sightseers by a wooden privacy fence.
Passersby might wonder what precious commodity is protected by all this foreboding security, and most would be very surprised to find
out!
For, behind the fencing and padlocks lies a little plot of land frequently referred to as the
"Body Farm" or "The Facility." It is the University
of Tennessee's Forensic Anthropology Facility,
the only one of its kind in the world, and the
research done here yields something very precious—ground-breaking forensic knowledge
that's priceless to law enforcement personnel
across the country and around the world.
The Impetus
The creation of a facility to chronicle the
process of decomposition was spurred by a
misidentification made by its founder Dr. Bill
Bass in 1977. An experienced anthropologist,
Dr. Bass was called upon to identify a body
believed to be that of a Civil War colonel killed
in battle and buried in a sealed lead coffin.
While examining the body, Dr. Bass observed a
bit of pinkish flesh still attached to the bones.
Based on his experience and the forensic
knowledge available at the time, he concluded
that the body had only been interred for about
a year. In reality, additional non-forensic clues
proved that the body was that of the colonel
and that Bass's estimate of the time of death
was about 112 years off! This made Dr. Bass
realize just how little was known about the
process of decomposition and motivated him
to gear his research toward expanding current
scientific knowledge about the decomposition
of bodies.
The Facility
It was 1977 and the original site the university
allowed the department to use was an old pig
farm about twenty miles away from the campus. After security became a problem at that
location, the university granted the department
ownership of an empty lot behind the medical
center that had previously been used to burn
the hospital's trash. Dr. Bass jumped at the
chance to have the facility located closer to the
university campus and in 1980 he and his students built a storage shed, had the area fenced
off, and the Body Farm was born.
In this unique outdoor laboratory, researchers
and graduate students study the process of
decomposition and how various environmental
conditions affect the rate and stages observed.
Scientists learn from watching bodies decompose, taking digital images at timed intervals,
and making meticulous notes. This careful
study has revealed much of what happens at
every stage of decomposition and is an invaluable tool for law enforcement officials to use
when evaluating crime scenes.
The facility typically houses over 20 corpses in
various stages of decomposition and in various
environmental conditions. Bodies are buried in
deep and shallow graves, submerged in water,
left out in the open in both shade and full sun,
covered with tarps, wrapped in plastic bags,
rolled inside carpets, or placed in one of the old
cars on the lot so that scientists and students
can observe how decomposition rates are
affected by conditions based in part on FBI files
of past crimes and the body disposal methods
used in those crimes.
Most of the bodies have been donated to the
facility for its research and some are unidentified bodies turned over by the medical examiner's office. As the awareness of the facility has
spread and more people will their bodies to the
facility, the University lawyers have had to draft
a special form for people to fill out for this purpose.
A true pioneer in his field, Dr. Bass has created
a unique "school" for scientists and law enforcement authorities alike. Of the 61 specialists certified nationwide by the American Board of
Forensic Anthropology, Dr. Bass trained onethird.
Agents from local and state law enforcement
departments and the FBI send field teams of
agents to the facility to participate in courses
that allow them to experience first-hand how
crime scenes might appear. Facility workers
prepare bodies to simulate crime scenes and
the agents are tasked with finding the bodies,
collecting evidence and evaluating the scenes.
The Process Begins
Decomposition begins as soon as a person
dies. The body starts to cool as the body's systems shut down and chemical changes start
the process. When a body decays, enzymes in
the digestive system begin to digest the tissues
surrounding it causing them to liquefy, called
putrefaction. At the same time, insects are
attracted to the body and begin their roles in
reducing it to skeletal remains. As the time
span between death and discovery widens,
forensic techniques become less accurate as
environmental variables begin to affect the
decomposition rate of the body and each environment has a different effect. For example, in
the summer heat, a body can be reduced to
bones in just two weeks. Bodies inside cars
decompose at a faster rate because it is much
hotter inside a car and the heat accelerates the
rate of decay. Bodies submerged in water,
wrapped in plastic, or located where the temperature is under 50° decompose slower for
various reasons. These variables and their
effects are the mysteries that Dr. Bass and his
colleagues are trying to unravel.
Insects Are The Key
In the first two weeks after death, insects are
one of the best indicators scientists have to
determine when death occurred. Different
insects will be interested in a body at different
stages of decomposition. By studying the different insect life cycles present on a cadaver, scientists can determine how long the insect has
been there. Cross-referencing that
information with known life cycles
and feeding habits of the particular
insect can estimate a fairly accurate time of death.
The cadaver-insect symbiosis can
also be a clue when two different
rates of decomposition are
observed, such as when a body is
decomposing in a house or car
and it has taken the flies and other
insects a while to find a way in.
Careful examination will show that
the body's natural decomposition
advanced before the insects began
their work.
An example of this was seen in a
case where Dr. Bass was asked to
help determine the time of death of
a family of three found dead in a
remote Mississippi cabin in
December 1993. There were clear
signs of a dual rate of decomposition, and this along with the insect
activity documented at the crime
scene enabled him to determine
the family died in mid-November, a
full month before the bodies were
"discovered" by a relative. Unfortunately for the
relative, that was also the time period when he
claimed to have visited the cabin and found
nothing amiss. Although he had an alibi for the
time around when the bodies were discovered,
he didn't have one for the time that they were
actually killed. With this information and other
evidence, authorities were able to convict the
relative of the murders.
The Chemistry of
Decomposition
A body releases about 450 known chemicals
during decomposition and researchers at the
facility are using an electronic nose with multiple sensors to sample the air above and around
a decomposing body to gather more clues to
establish a time of death.
Decomposing bodies also leak fatty acids onto
the surface where it rests. The profiles of these
acids changes as the days pass and analyzing
them can reveal the time of death. It can also
give clues as to how long the body has been in
a particular spot and if it may have been moved
after death.
To achieve this, perforated pipes are situated
above and below the bodies and emissions are
collected with sorbent traps. The chemicals are
extracted and analyzed by gas chromatography
and mass spectrometry to be identified and
quantified. Then they are mapped along with
the environmental factors present during their
collection to allow scientists to construct a timeline to determine time of death.
Future Hopes
As work at the facility continues and bright
young graduate students continue to filter
through the program, new technologies are an
inevitable result. Scientists theorize that the
research being done at the Facility may be
used in the future to develop sprays to train
cadaver dogs or hand-held monitors that can
detect the smells of decomposition at crime
scenes. As the mysteries of death are unraveled and a detailed analysis of decomposition
continues to be formulated, these new technologies will make it easier for law enforcement
to identify victims, find the perpetrators and
ensure that these most heinous of crimes will
not go unpunished.
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