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ORNL project seeks to pinpoint time since death
OAK RIDGE, Tenn.,
June 7, 2000
Determining when a crime victim died can make the difference between a criminal going free or being brought to justice, and researchers at Oak Ridge National Laboratory (ORNL) are developing a system that could help justice prevail.
Arpad Vass of the Department of Energy's ORNL and colleagues at the University of Tennessee (UT) are examining time-dependent chemical and biological markers in hopes of gaining a better understanding of the cadaver decay process.
"Our ultimate goal would be to develop a tricorder-like device that we could wave over a body to tell us how long the person has been dead," Vass said. "Short of that, we're developing a model that would allow forensic scientists to insert data into a chart or computer program to determine how long a person has been dead."
If law enforcement agents find a body within 12 to 24 hours, forensics experts have techniques to determine time since death - plus or minus four hours. But it becomes more complicated if a body is found several days later. And in warm climates or during the summer, a body can be reduced to bones in just 30 days, Vass said.
To develop one of their models, Vass is focusing on tissue analysis and hoping to determine which organ provides the best indication of how long a person has been dead. Lungs are the first to decay. As a body decomposes, proteins break down into amino acids and progressively smaller molecules. By studying whether there is a constant rate at which the large molecules of the body break down, Vass believes he can develop a computer program that correlates the percentage of larger molecules to small ones with a number of days.
As part of the project, Vass and UT graduate students Jennifer Love and Jennifer Synstelien take daily tissue samples from cadavers at the Anthropological Research Facility in Knoxville. The internationally known facility contains anywhere from 10 to 24 bodies at any one time that have been donated to the program in the hopes of helping science and law enforcement.
"Each year, there are about 90,000 homicides in this country," Vass said, "and for every one, you need to know when the person died. Our research can help answer the where and when, and that should help law enforcement officials solve crimes."
Vass' research is also aimed at telling whether the body has been moved from where death occurred.
"We can tell if a body has been moved by looking at volatile fatty acids in the soil or whatever is under the body," said Vass, of ORNL's Life Sciences Division. "If these fluids - or even traces - aren't present, the body didn't decay there."
While Vass is concentrating on tissue analysis, Love, a graduate assistant in UT's Department of Anthropology, is focusing on aroma scan technology. Her goal is to use an electronic nose with 32 sensors and identify a unique signature that would look for changes over time. It is something that could be used by police officers in the field to help locate bodies.
"Although our ultimate goal would be to develop an odor-sensitive instrument that would tell us time since death, initially we're studying changes in odor pattern and intensity," Love said. "By systematically studying these changes as a body decomposes and correlating the changes to temperature and humidity, we hope to gain a better understanding of this process as it relates to locating a corpse."
Vass is convinced the research will result in the development of a scientific protocol for determining time since death that will eliminate the uncertainty involved with using methods that rely on observation and opinion.
The research is funded by DOE. ORNL is a multiprogram research facility operated by UT-Battelle.