Local News

Forensic entomologists use flies to help solve crimes

Posted April 7, 2010 12:12 a.m. EDT
Updated April 12, 2010 5:03 p.m. EDT

— Investigators often turn to entomologists for help solving violent crimes. By studying the life cycle of flies, entomologists can often determine when a person died, where they died and sometimes how they died.

"It's really kind of putting all the pieces of a puzzle together," said Dr. Wes Watson, a veterinary entomologist with North Carolina State University. “They're not going to fool you or lie to you, because they're just doing what they do naturally."

Watson said when a dead person’s body is left outside, insects descend. Millions can populate a body when it’s exposed to nature’s elements.

"There are certain chemical queues that tell them (flies) that there is a body there, and they're attracted to that body. They come in, the females lay their eggs, and they start the decomposition process,” Watson said.

Law enforcement officers are using the data provided by files to help fill in the gaps with homicide investigations. Finding out the circumstances surrounding a person’s death can be difficult when a body is in an advanced state of decay. That is where the flies come in.

“The size and length of the flies, and how fast they're growing, we can then calculate then how old they are, and come up with an estimate on when the insects arrived at the body,” Watson said.

Watson's expertise has been used in several high-profile homicide cases, including the deaths of several women in Edgecombe County.

The remains of eight women have been found over the past four years – seven in rural Edgecombe County and one in Halifax County. Each was black, had a history of drugs or prostitution and had disappeared. Entomologists are helping determine additional information about the women, whose decomposed bodies were often found in wooded areas.

Entomology is also being used in the Brad Cooper case. He is charged with killing his wife nearly two years ago. Her body was found in an undeveloped subdivision near the couple's Cary home.