281 lines
15 KiB
Plaintext
281 lines
15 KiB
Plaintext
|
July 1990
|
|||
|
|
|||
|
|
|||
|
THE FORENSIC ANTHROPOLOGIST
|
|||
|
|
|||
|
By
|
|||
|
|
|||
|
Robert W. Mann, M.A.
|
|||
|
and
|
|||
|
Douglas H. Ubelaker, Ph.D.
|
|||
|
Physical Anthropologists
|
|||
|
Department of Anthropology
|
|||
|
Smithsonian Institution, Washington, D.C.
|
|||
|
|
|||
|
|
|||
|
In recent years, just as the investigation of a crime scene
|
|||
|
has become more complex and sophisticated, so has the task of the
|
|||
|
forensic anthropologist. Forensic anthropologists assist medical
|
|||
|
and legal specialists to identify known or suspected human
|
|||
|
remains.
|
|||
|
|
|||
|
The science of forensic anthropology includes archeological
|
|||
|
excavation; examination of hair, insects, plant materials and
|
|||
|
footprints; determination of elapsed time since death; facial
|
|||
|
reproduction; photographic superimposition; detection of
|
|||
|
anatomical variants; and analysis of past injury and medical
|
|||
|
treatment. However, in practice, forensic anthropologists
|
|||
|
primarily help to identify a decedent based on the available
|
|||
|
evidence.
|
|||
|
|
|||
|
For example, when a skeleton found in a wooded area is
|
|||
|
brought to a morgue or an anthropologist's laboratory for
|
|||
|
examination, the first step is to determine whether the remains
|
|||
|
are human, animal, or inorganic material. If human, an
|
|||
|
anthropologist then attempts to estimate age at death, racial
|
|||
|
affiliation, sex, and stature of the decedent.
|
|||
|
|
|||
|
If the skeleton shows evidence of prolonged burial or
|
|||
|
is accompanied by coffin nails or arrow points, it usually
|
|||
|
represents an historic or prehistoric burial rather than a recent
|
|||
|
death. Construction crews frequently unearth such skeletons
|
|||
|
during road or housing excavations. After combining all of the
|
|||
|
evidence, the anthropologist determines the skeleton's possible
|
|||
|
significance to medical and legal authorities.
|
|||
|
|
|||
|
Although the primary task of anthropologists is to establish
|
|||
|
the identity of a decedent, increasingly they provide expert
|
|||
|
opinion on the type and size of weapon(s) used and the number of
|
|||
|
blows sustained by victims of violent crime. It should be noted,
|
|||
|
however, that forensic pathologists or related experts in
|
|||
|
forensic medicine determine the cause or manner of death, not the
|
|||
|
forensic anthropologist.
|
|||
|
|
|||
|
Most anthropologists have advanced degrees in anthropology
|
|||
|
and have examined hundreds of remains. They are also thoroughly
|
|||
|
familiar with human anatomy and how it varies in different
|
|||
|
populations. Some anthropologists may also have experience in
|
|||
|
police science or medicine, as well as in serology, toxicology,
|
|||
|
firearms and toolmarks identification, crime scene investigation,
|
|||
|
handling of evidence, and photography. A limited number of
|
|||
|
anthropologists deal with footprint analysis and species
|
|||
|
identification of carrion insects in relation to estimating time
|
|||
|
elapsed since death.
|
|||
|
|
|||
|
Perhaps the anthropologist's most valuable skill is
|
|||
|
familiarity with subtle variations in the human skeleton.
|
|||
|
Although most adult skeletons have the same number of bones
|
|||
|
(206), no two skeletons are identical. Therefore, observations
|
|||
|
of patterns or unique skeletal traits frequently lead to positive
|
|||
|
identifications. The most frequently used method for
|
|||
|
identification is to compare before- and after-death dental
|
|||
|
photoimages. If such photoimages do not exist, or if they are
|
|||
|
unavailable, then old skeletal injuries or anatomical skeletal
|
|||
|
variants revealed in other photoimages may provide the
|
|||
|
comparative evidence necessary to establish a positive
|
|||
|
identification.
|
|||
|
|
|||
|
HYPOTHETICAL EXAMPLE
|
|||
|
|
|||
|
Suppose hunters find a partially clothed skeleton lying on
|
|||
|
the ground in a heavily wooded area with much of its clothing
|
|||
|
torn and scattered by carnivores. Law enforcement officers are
|
|||
|
called to the scene, as is the medical examiner or nonphysician
|
|||
|
coroner. The scene is photographed in detail, and the skeleton
|
|||
|
is examined and photographed before being removed to the city
|
|||
|
morgue.
|
|||
|
|
|||
|
At the morgue, the medical examiner examines the remains for
|
|||
|
evidence of trauma, such as stab marks in the shirt, blunt trauma
|
|||
|
to the skull and mandible, and broken bones. Photoimages and
|
|||
|
photographs of the body show that no bullets or pellets having
|
|||
|
been noted. Also, examination of the clothing reveals no wallet
|
|||
|
or other personal identification.
|
|||
|
|
|||
|
The medical examiner determines through measurement of the
|
|||
|
pubic area that the remains are those of a middle-aged adult
|
|||
|
male. There is no evidence of facial or head hair to aid in
|
|||
|
determining racial affiliation. From measurements taken at the
|
|||
|
scene, the examiner roughly estimates the stature. Also, a
|
|||
|
forensic odontologist is called in to take dental photoimages.
|
|||
|
Although the decedent has a number of large dental cavities, he
|
|||
|
shows no restorations or evidence of having seen a dentist. At
|
|||
|
this point, the medical examiner requests assistance from a
|
|||
|
forensic anthropologist, who conducts further study of the
|
|||
|
remains in the laboratory.
|
|||
|
|
|||
|
The forensic anthropologist's examination confirms the
|
|||
|
medical examiner's findings that the individual is a middle-aged
|
|||
|
male. However, questions remain that the forensic anthropologist
|
|||
|
must answer, such as:
|
|||
|
|
|||
|
. What is the individual's racial affiliation?
|
|||
|
|
|||
|
. What is the individual's age and stature?
|
|||
|
|
|||
|
. How long has the individual been dead?
|
|||
|
|
|||
|
. Is there any evidence of trauma or foul play at or near the
|
|||
|
time of death?
|
|||
|
|
|||
|
. Are there any distinguishing skeletal traits that may aid in
|
|||
|
establishing the identity?
|
|||
|
|
|||
|
. Is there any indication of post-mortem treatment or
|
|||
|
alteration of the remains?
|
|||
|
|
|||
|
Racial Affiliation
|
|||
|
|
|||
|
The question of racial affiliation is difficult to answer
|
|||
|
because, although racial classification has some biological
|
|||
|
components, it is based primarily on social affiliation.
|
|||
|
Nevertheless, some anatomical details, especially in the face,
|
|||
|
often suggest the individual's race. In particular, white
|
|||
|
individuals have narrower faces with high noses and prominent
|
|||
|
chins. Black individuals have wider nasal openings and subnasal
|
|||
|
grooves. American Indians and Asians have forward-projecting
|
|||
|
cheekbones and specialized dental features.
|
|||
|
|
|||
|
Examination of this skeleton reveals traits consistent with
|
|||
|
white racial affiliation. Further examination of the skull
|
|||
|
produces a few strands of straight blonde hair. Microscopic
|
|||
|
examination shows the hair to be consistent with that of a white
|
|||
|
person.
|
|||
|
|
|||
|
Age and Stature
|
|||
|
|
|||
|
Usually, examination of the pubic bone, sacroiliac joint,
|
|||
|
amount of dental wear, cranium, arthritic changes in the spine,
|
|||
|
and microscopic studies of bones and teeth narrows the age
|
|||
|
estimate given by the anthropologist. After examining the
|
|||
|
skeleton, these indicators suggest that the man was between 35
|
|||
|
and 45 years of age at the time of death.
|
|||
|
|
|||
|
Estimation of stature can be narrowed by measuring one or
|
|||
|
more complete long bones, preferably a femur or tibia. If
|
|||
|
stature estimates are based on incomplete long bones, less
|
|||
|
confidence can be placed in them. This measurement of the
|
|||
|
maximum length of the bone can then be plugged into a formula
|
|||
|
based on race and sex to produce an estimate. In this case the
|
|||
|
individual's stature was estimated at 5'7'' to 5'9'' with a mean
|
|||
|
stature of 5'8.''
|
|||
|
|
|||
|
Time Interval Since Death
|
|||
|
|
|||
|
Estimating the time interval since death can be extremely
|
|||
|
difficult. For the most part, such an estimate is based on the
|
|||
|
amount and condition of soft tissue, such as muscle, skin, and
|
|||
|
ligaments present, the preservation of the bones, extent of
|
|||
|
associated plant root growth, odor, and any carnivore and insect
|
|||
|
activity. However, many other variables must also be considered,
|
|||
|
including the temperature at the time of death, penetrating
|
|||
|
wounds, humidity/aridity, soil acidity, and water retention. The
|
|||
|
longer the time since death, the more difficult it is to
|
|||
|
determine the time interval since death. In this hypothetical
|
|||
|
example, the anthropologist determined that the individual died
|
|||
|
6 to 9 months previously, based largely on the condition of the
|
|||
|
soft tissue and the amount of root growth in the individual's
|
|||
|
clothing.
|
|||
|
|
|||
|
Evidence of Trauma
|
|||
|
|
|||
|
After the dirt and forest debris were removed from the bones
|
|||
|
using water and a soft brush, a number of faint cuts became
|
|||
|
visible in the left ribs and the mid-back. The number of
|
|||
|
discrete cuts in three ribs and in one vertebra suggest that this
|
|||
|
male was stabbed a minimum of three times. No additional
|
|||
|
evidence of trauma was noted.
|
|||
|
|
|||
|
Distinguishing Skeletal Traits
|
|||
|
|
|||
|
Further examination revealed that the male sustained a
|
|||
|
fracture above his right eye and upper jaw bone at least several
|
|||
|
years before death. The individual also had a severely deviated
|
|||
|
nasal septum and presented evidence of a severe chronic nasal
|
|||
|
infection. This observation is noteworthy because if he sought
|
|||
|
medical help for the fractures or sinus condition, photoimages
|
|||
|
may have been taken that would provide an excellent opportunity
|
|||
|
for positive identification.
|
|||
|
|
|||
|
POST-EXAMINATION PROCEDURES
|
|||
|
|
|||
|
After the forensic anthropologist completes the
|
|||
|
examination, the medical examiner provides all information
|
|||
|
obtained from the skeleton to the law enforcement officials
|
|||
|
investigating the case. The information is then entered in the
|
|||
|
National Crime Information Center (NCIC).
|
|||
|
|
|||
|
In this hypothetical case, after several months, a search
|
|||
|
failed to locate a missing person matching this description.
|
|||
|
Therefore, the medical examiner and the detectives returned to
|
|||
|
the forensic anthropologist to request that a facial
|
|||
|
reproduction be attempted.
|
|||
|
|
|||
|
Two approaches are available to an anthropologist in
|
|||
|
reconstructing facial appearance during life. First, the
|
|||
|
anthropologist could work with a composite artist experienced in
|
|||
|
rendering sketches based on information supplied by eyewitnesses.
|
|||
|
Or, the anthropologist could call in a specialist in
|
|||
|
three-dimensional facial reproduction, a technique in which the
|
|||
|
head is constructed in clay directly over the skull and mandible
|
|||
|
or over good casts of them. Because of limited funds, and
|
|||
|
because an experienced composite artist is available on staff,
|
|||
|
the forensic anthropologist and artist worked together to produce
|
|||
|
a drawing of the person represented by the skeletal remains.
|
|||
|
This drawing was then made available to the public via the local
|
|||
|
media.
|
|||
|
|
|||
|
Shortly thereafter, two unrelated men who had seen the image
|
|||
|
on television came forward because they thought that it might be
|
|||
|
a relative. Medical and dental records for both individuals
|
|||
|
could not be located, but facial photographs taken within the
|
|||
|
last 2 years were available.
|
|||
|
|
|||
|
Using new techniques of photographic superimposition and
|
|||
|
comparison, the forensic anthropologist excluded one of the
|
|||
|
individuals outright. However, frontal photoimages of the second
|
|||
|
individual taken 3 years before death showed the individual was
|
|||
|
treated for facial injuries sustained in a motor vehicle
|
|||
|
accident. The configuration of the frontal sinuses on the
|
|||
|
photoimages matched exactly the photoimages of the recovered
|
|||
|
skull, thereby positively identifying the victim.
|
|||
|
|
|||
|
VALUE OF FORENSIC ANTHROPOLOGY
|
|||
|
|
|||
|
A forensic anthropologist makes significant contributions to
|
|||
|
an investigation. The greatest of these could well be the
|
|||
|
anthropologist's intensive training and experience in
|
|||
|
distinguishing between human and nonhuman remains, determining
|
|||
|
age at death, racial affiliation, sex, stature, elapsed time
|
|||
|
since death, skeletal trauma, post-mortem damage and alteration
|
|||
|
of the skeleton, and establishing positive identification based
|
|||
|
on skeletal and dental evidence. Such information can be
|
|||
|
obtained from complete bodies or those partially destroyed by
|
|||
|
burning, air crashes, intentional mutilation and dismemberment,
|
|||
|
explosions, or other mass disasters. In fact, a forensic
|
|||
|
anthropologist is now an integral member of most mass disaster
|
|||
|
teams.
|
|||
|
|
|||
|
Through their anthropological training, most forensic
|
|||
|
anthropologists have knowledge of excavation techniques and
|
|||
|
mapping that are invaluable in recovering evidence.
|
|||
|
Consequently, the forensic anthropologist should participate in
|
|||
|
the investigation of the crime scene and, especially, in the
|
|||
|
recovery of human skeletal remains.
|
|||
|
|
|||
|
CONCLUSION
|
|||
|
|
|||
|
Many forensic anthropologists offer their services to law
|
|||
|
enforcement agencies, coroners, and medical examiners. However,
|
|||
|
if a law enforcement agency does not have access to a forensic
|
|||
|
anthropologist, experienced experts can be found in many of the
|
|||
|
larger universities, in anthropology museums throughout the
|
|||
|
United States, and in some medical examiner's offices. It should
|
|||
|
be noted, however, that not all physical anthropologists are
|
|||
|
qualified to practice forensic anthropology. A list of board
|
|||
|
certified forensic anthropologists can be obtained from the
|
|||
|
American Academy of Forensic Sciences. Forensic anthropologists
|
|||
|
have much to contribute to law enforcement and would welcome
|
|||
|
the opportunity to assist in the successful resolution of an
|
|||
|
investigation.
|
|||
|
|