Stable isotope forensics offers hope in homicides
Canadian police are using an advanced forensic technique to help determine the identity of a homicide victim who may have traveled or lived in the area around New York City in the months before he died in the late 1990s.
The forensic tool, known as stable isotope analysis, determines the concentration of certain isotopes in the body, which in turn can help show where a victim may have been before death. Isotopes are variations of basic chemical elements and are deposited in hair and bone through food and water consumption.
Experts say isotopes can eliminate 90 percent of the world in an attempt to identify a homicide victim and have been used to solve European criminal cases.
Could stable isotopes be useful in the Gilgo Beach investigation, where four sets of remains are still unidentified?
"Absolutely," said retired detective Paul Dostie, of Mammouth Lake, Calif., who used the method to find the town in Mexico where a still-unidentified female slaying victim came from. "When you don't have a match in a DNA database, you don't give up; you go to other resources like stable isotope analysis."
Suffolk County Medical Examiner Yvonne Milewski said she was familiar with the isotope technique.
"We are aware of the use of stable isotope analysis of human remains in human investigations. We cannot comment on the ongoing Gilgo investigations. As a general policy, the medical examiner's office would consider pursuing any scientific method that could potentially provide additional information, and possibly assist in a criminal investigation."
Asked if her office has ever used the technique, Milewski said through a spokeswoman that it had not been used in any "closed" case and declined to comment further when asked if it was used in any open cases.
Deputy Chief Kevin Fallon, spokesman for the Suffolk County police department, also said investigators were aware of the isotope method and would use it if it were deemed helpful. However, Fallon declined to comment on whether the method has or is being used in any homicide or missing person case, in contrast to the NYPD and Nassau County police, where spokesmen said their departments had never used it.
While the Canadian homicide victim, who tests showed was born around 1958, has yet to be identified, police used isotope analysis to narrow down the geographic area where he lived and traveled. The zone is an oval shaped area encompassing Newfoundland in eastern Canada, northeastern Pennsylvania, New York State and New England. The southern edge of the zone includes a fringe of the north Bronx, as well as nearby suburban counties.
A smaller search area allows police to focus their investigation of missing person databases so they aren't looking for a needle in a giant haystack, said superintendent John House, of the Royal Newfoundland Constabulary.
"This allows you to make that haystack smaller," said House. "It doesn't eliminate the haystack; it makes it a lot smaller."
After a photo of a reconstruction of the man's head and face circulated in newspapers in eastern Canada, investigators got a number of calls but no DNA match, said House. Looking for new leads in the United States, House provided the image to Newsday.
House turned to isotope analysis by contacting Wolfram Meier-Augenstein, an expert in isotopes, at the James Hutton Institute in Scotland. (Police labs can't do isotope analysis in-house.) The science turns on the adage that "we are what we eat," explained Meier-Augenstein in a telephone interview. While isotopes are plentiful in nature, they are deposited in water and food substances at different rates depending on geographic location, said Meier-Augenstein. For instance, North American people consume more corn products than Europeans so the isotope signature for the Carbon-13 isotope would be greater than in a European person, whose primary source of dietary sugar would be from sugar beets.
Global distribution rates of stable isotopes for hydrogen and oxygen can be mapped globally, although there are some variations, noted Meier-Augenstein. Because a person absorbs stable isotopes from food and water, hair will act as a recorder, providing a roadmap about a person's travel and help focus an investigation, he said.