Narrowing the field: How forensic anthropologists help solve cases

As police continue to look for clues in the disappearance and death of Katelyn Markham, whose skeletal remains were found in rural Indiana earlier this week, they will undoubtedly turn to science for help.

And to the educated eye of forensic anthropologist Elizabeth Murray, a biology professor at the College of Mount St. Joseph in Cincinnati, human remains can tell a story.

Murray, who works with coroners in Hamilton, Butler and Montgomery counties, said cases are few and far between. Police and prosecutors say the expertise she and other scientists bring is vital to their investigations – and can be the key in solving and prosecuting crimes.

In the case of the skeletal remains discovered in rural Indiana identified as those of Markham, the 21-year-old Fairfield woman who had been missing since August 2011, investigators will likely turn to a forensic anthropologist to help determine how she died. The cause of Markham's death is unknown and while police are investigating, they have not yet determined if she was a victim of violence.

Franklin County, Ind. Coroner Wanda Lee said that the remains remain in the custody of Hamilton County, where tests will likely be performed for weeks and possibly months.

For Cincinnati homicide unit Sgt. Mike Miller, scientific evidence is of "paramount importance."

"If you go into court with the CSI-effect in full force, meaning people watch TV and expect us to reproduce what they see on TV, science is the only thing that bridges the gap between fantasy and reality," Miller said.

Miller said there are two forms of identification that are beyond challenge – the fingerprint and DNA. Science can put people at scenes and unites with "old shoe leather investigations." The investigator's ability to obtain information through traditional avenues is vital, but the science is the foundation for which that information rests upon, Miller said.

Forensic Anthropology And Its Application

Positively identifying skeletal remains is a detailed and a tedious process for forensic anthropologists. Forensic anthropologists can examine skeletal remains to determine the sex, age, height and ancestry, Murray said.

"Bones and teeth last a long time, we have them from prehistoric humans; we have them from dinosaurs and that's the point of forensic anthropology – when all the soft tissue is gone, that's all we have left to work with," Murray said.

Although the coroner's office may be conducting autopsies on a regular basis, the discovery of skeletal remains is fairly rare, Murray said.

"I may only get a couple cases for an entire year" Murray said. "Students will contact me saying they want to be a forensic anthropologist, and I often say, ‘I do, too, but I have to teach college for a living; it's not like on TV.'"

The first step is to determine if the remains are human, which is done by examining the shape and the way the bones relate to each other. All animals share similar skeletal models, meaning we all have the same bones in similar areas, Murray said. But the difference is in the joint surfaces and muscle-attachment sites, compared to a bird or a four-legged animal.

"The next step after determining the remains are human, we go to the age because in an adult you'll able to determine something about sex and something about stature," Murray said. "You can look at the pelvis, you can look at the markers on the skull, take measurements of the bones and feed them into computer formulas to determine the probability of the sex."

Puberty will cause the female pelvis to spread from side-to-side and from front-to-back to accommodate for childbirth, as opposed to a male pelvis is heavily influenced by the hormone testosterone.

"Whether a guy is a couch potato or a bodybuilder, his higher testosterone levels generally means his joint surfaces are bigger and his muscle-attachment sites are generally larger," Murray said.

To determine age, forensic anthropologists inspect whether growth plates have fused and the parts of a skeleton that typically deteriorate with age. Taking skull measurements and comparing them to a database of skulls of known ancestry is the method used to establish ancestry.

Forensic anthropologists develop a biological profile, which narrows the field of possible missing persons authorities are investigating.

Law enforcement officers are familiar with the descriptions of missing persons and can then use the biological profile to solve the case. For forensic anthropologists, finding distinctive traits of a skeleton can be used to crosscheck dental and medical records.

"If I see any kind of hip prosthesis or an old broken bone, we narrow the field even more," Murray said. "There are unique features where I can say to the investigators, ‘if you have an X-ray or CT scan of that missing person, we can narrow this down.'"

Forensic anthropologists can pinpoint evidence of a traumatic injury, such blunt force trauma or a stab wound, but forensic anthropologists are not legally allowed to determine cause and manner of death, Murray said. That's the job of a forensic pathologist, medical examiner or coroner.

Forensic anthropologists are also qualified to assess the conditions involving a person's death, by analyzing skeletal trauma and separating the injuries caused by various instruments.

"I may be able to say to the coroner's office how many blunt trauma injuries there are to the skull, or even what sequence or what direction they came from," Murray said. "We just give information."

Determining how long remains have been in the area is another aspect where forensic anthropologists assist criminal investigators. Often, the scientists use clues on and around the skeleton to determine how long the remains have been in an area, which depends on the skeleton's access to insects and carnivores.

"If moss is growing on the skeleton, that suggests [it has] been there for a while," Murray said. "Determining how long a skeleton has been some place is pretty difficult, there are just so many variables that can go into that."

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