Uploaded by Molly Brown

Forensic Anthropology Lab Activity

Forensic Anthropology
Case Study: JohnWayne Gacy
On a cold December day in 1978 police encountered the home of John Wayne Gacy Jr., a
known sex offender. They were there to investigate the disappearance of a 15-year-old boy
who had been offered a job by Gacy. A search of the Gacy house ultimately revealed a
number of incriminating items related to the disappearances of other youngsters. Gacy
finally confessed to police that he killed at least thirty people and buried most of the remains
of the victims under the crawl space of his house. Buried beneath the crawl space or in his
garage were twenty-eight young male victims. Gacy disposed of five bodies in a nearby
river when he ran out of room in the crawl space, and because he had been experiencing
back problems digging the graves. Police faced the horrific responsibility of identifying the
remains of the victims.
The victims were so alike in age, race, and stature that police initially were unable to
make individual identifications for most of the victims. Some of the victims had been buried
on top of older graves, co-mingling their remains. Clyde Snow, the world-renowned forensic
anthropologist from Oklahoma, was asked to help investigators make the difficult
Snow began by examining each skeleton to make sure each of the bones was
correctly attributed to an individual. Once he was sure all the bones were sorted properly,
the in-depth study began. Long bones like the femur (thigh bone) were used to estimate
each individual’s height. This helped to narrow the search when attempting to match the
victims with the descriptions of missing persons. Next, Snow made a thirty-five-point
examination of each skull for comparison to known individuals.
After narrowing the possibilities to those missing persons fitting the general description,
investigators were left with their hospital and dental records. Evidence of injury, illness,
surgery, or other unique skeletal defects were used to make an identification. Snow also
pointed out features which gave clues to the victims’ behavior and medical history. He
discovered that one of Gacy’s victims had an old fracture of his left arm, and that his left
scapula (shoulder blade) and arm bore the tell-tale signs of a left-handed individual. These
details were matched to a missing persons’ report and another young victim was identified.
For the most difficult cases, Snow called in the help of forensic sculptor and facial
reconstructionist Betty Pat Gatliff. She used clay and depth markers to put the flesh back on
the faces of these forgotten boys in the hopes that someone would recognize them after
their photographs were released to the media. While her reconstruction efforts were
successful, not a single definite identification resulted. Investigators found some families
unwilling to accept the idea that their loved one was one of Gacy’s victims. Even with
Gatliff’s help, nine of Gacy’s victims remained unidentified.
In 1994, Gacy was executed by lethal injection.
1 inch = 2.54 cm
Part One: Class Data (abbreviated)
Measure (to your best ability) your femur, humerus & radius. Then use the table above to estimate your height.
Compare it to your actual height. Note differences - What can account for that?
Table 1: Using Femur
How close was the calculated height compared to actual heights?
Table 2: Using Humerus
Length (cm)
Height (cm)
Height (Cm)
How close was the calculated height compared to actual heights?
Table 3: Using Radius
Length (cm)
Height (cm)
Height (cm)
How close was the calculated height compared to actual heights?
Based on your calculations, if you had the luxury of analyzing an entire skeleton, which bone would
you use to calculate an estimate of height?
Part Two: Mr. or Mrs. Seemore(a) Bones???
Look at the skeleton in the front of the classroom. Use your knowledge about markers/patterns which
can lead to a biological profile. Record your hypotheses & support with direct observations.
1. What gender is it? Give 4 reasons for your answer.
2. What is your best guess on race? Why?
3. Approximate height? What did you use?
Part Three: Human Dentition
1. Each person should get a Styrofoam strip and place their initials on both top & bottom.
2. Gently bite down on the Styrofoam so that your incisors and canine teeth are in contact with
the material. DO NOT BITE THROUGH IT!
3. Carefully wipe away any saliva with a tissue. Label each side with “Upper” and “Lower”.
4. Measure the distance between your canine teeth of your upper and lower jaw.
5. Gather 5 female measurements and 5 male measurements in the class. Take the average.
6. Complete the case study questions.
SKETCH your upper and lower impressions - label incisors (including shape), Label
shape of dental arch, and measure the canine to canine distance in your maxilla.
Male Name
Canine to canine (cm)
Female Name
Canine to canine (cm)
Teeth Analysis
1. Is there a difference between male and female measurements?
2. What differences might you find with adolescents vs. adults?
Give the Race of the following pieces of evidence based on anthropological markers.
Support with evidence.
Justification Junction
Think back to the SVU episode we watched. What stands out to you as “not
realistic” after you learned more about the science behind forensic
anthropology used to build a biological profile? Please list at least two points
and explain why you feel they are not realistic.
Forensics on Trial:
What was wrong with how they interpreted the evidence in the Sabina Kulakowski case?
How did they eventually clear Roy Brown’s name?
After watching the case regarding bite mark analysis. Explain at least two sources of error
that are innate to this technique.
In your opinion - is this enough to “do away” with this technique? What would your
recommendations be to improve the science of bite mark analysis?