Hair-Raising Advances

by Andrea Campbell

How do police stay on top of criminals? By pushing the boundaries of science.

In the fall of 2000, hunters came upon the remains of a female murder victim near Interstate 80, west of Salt Lake City, at the south end of Great Salt Lake. Twenty-six bones, some hair, a tee shirt and a necklace were all that detectives found. The victim would have been about 5 feet tall, age 17 to 20. A facial reconstruction was formed a few months later and publicized nationally, but the identity is still unknown.

“We don’t know who she is,” says Sheriff’s Detective Todd Park, of Salt Lake County, “We don’t even know the cause of death.” But Park heard about using a new type of hair analysis and contacted the inventors in an effort to identify the murdered woman. “It’s a phenomenal method,” says Park, a member of his department’s cold case homicide unit, “I think it will help the law enforcement community a great deal.”

“You are what you eat and drink—and that is recorded in your hair,” says geochemist Thure (pronounced Tur-ee) Cerling, who led a new research effort with Jim Ehleringer, a distinguished professor of biology at the University of Utah, where Cerling is also a professor of geology, geophysics, and biology. Three years ago, they co-founded IsoForensics, Inc., a company that uses stable isotope analysis of forensic substances to find slight variations in a chemical element’s makeup.

Ehleringer developed a method now used by the U.S. Drug Enforcement Administration to help learn where cocaine or heroin were produced, based on local variations in carbon, nitrogen, hydrogen and oxygen isotopes absorbed into coca and poppy plants from soil and water. This same type of analysis and technique was used to help track counterfeit $100 bills, based on water used to grow the cotton with which the bills were made!

Recently Cerling and Ehleringer conducted a study that Ehleringer says, “We have found significant variations in hydrogen and oxygen isotopes in hair and water that relate to where a person lives in the United States. Police are already using this to reconstruct the possible origins of unidentified murder victims.”

So a single hair can help determine a person’s location during recent weeks to years, depending on the length of the hair sample and how much time it took to grow.

After hearing of Ehleringer’s research, Park contacted the team and arranged for the isotope analysis of his victim’s hair. “The samples I gave to Jim told me her approximate location for the last two years of her lifetime. She moved around within the Northwest—mainly in the Idaho-Montana-Wyoming area . . .”

After scientists conduct more tests on the woman’s teeth, they are hoping the isotopes may reveal where her teeth formed when she grew up. Then Park will check out missing persons records in areas the victim lived in hopes of identifying her. “Every little bit helps,” the detective says. “You put the pieces of the puzzle together to get a whole picture. And this is definitely something that will give us a piece of the puzzle.”

* See color-coded maps created by the team, showing how ratios of hydrogen and oxygen isotopes in scalp hair vary in different areas of the U.S. http://www.newswise.com/images/uploads/2008/02/19/thumbs/IsotopeMapsSimple.jpg

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