The bugs crawl in, the bugs crawl out

What kind of man lurks in dark, steamy jungles studying the insects he finds on corpses? It's all in a night's work when you're a forensic entomologist.

By Christopher Kemp

Dec 13, 2000 | On a still Hawaii morning, a telephone rings, cutting through the silence; a body has been found dumped in a sugar cane field. M. Lee Goff dresses, gathers his kit and drives to the crime scene to collect maggots, beetles and other insect species from the decomposing corpse. Goff's movements are practiced, like a ritual; his hands are quick and confident. He has done this many times before.

A forensic entomologist at the University of Hawaii at Manoa on the island of Oahu, Goff uses insect evidence to help police and medical examiners solve crimes. He is one of only a handful of forensic entomologists actively working in the field and conducting forensic research studies -- he calls the group the "Dirty Dozen." In Goff's recently published book, "A Fly for the Prosecution: How Insect Evidence Helps Solve Crimes," he outlines some common methods and applications of forensic entomology.

The number of forensic entomologists working with investigators is small because insects are involved in relatively few cases, Goff says. "You've got a limited period of time during the year when insects get involved," he says. "Some years I'll do about 10 or 11 cases, and other years it will be about 20 or 25." Despite variations from one year to the next, the average number of cases has increased over time, Goff says, as medical examiners and police have slowly begun to accept his sampling methods.

Goff first learned of forensic entomology in 1983 while attending a seminar about insect evidence and murder investigations as a young mite specialist. Intrigued, Goff contacted the local medical examiner and offered assistance whenever he heard about a suspicious death involving a badly decomposed body.

When the slick, humid rain forest offers up another bloated murder victim, Goff pulls on his boots and heads out with specimen-collecting gear in hand, eager to find some meaning in the insects that have made a home of the body.

It has taken many years for conventional crime investigators to accept forensic entomology as a useful tool, Goff says. "You are very much like a circus sideshow," he says. As "an academic coming into a typical crime scene, you don't necessarily think the same way [as the police]."

Depending on the species collected at the scene and their stages of development, insects can be used to establish several things about a body after death. Most commonly, forensic entomology is used to determine the postmortem interval, or the time between the death and the discovery of the body, but it also can help establish whether the body was moved after death and if poisons, drugs or toxins were involved. Further, since the advent of sensitive DNA testing, blood collected from the intestinal tracts of insects at the crime scene has been used to identify rape and murder suspects.

Goff usually finds numerous species of insects at a crime scene: blowflies, flesh flies and black soldier flies; moths, wasps, ants and mites; beetles, spiders and scorpions. Each species plays a unique and characteristic role in the decomposition of a body, he says. Flies are the first to arrive; attracted early by the smell of decomposition, they colonize soft parts of the corpse -- like open wounds or the ears, mouth, nose and eyes. Next are the social insects such as predatory ants and wasps, which wait until after the maggots and flies on which they feed have settled in the body. Others, like the lumbering hide beetle, wait to feed on the cartilage and dried tissue that remain after most of the other species are gone.

This pattern, with different species invading the body in distinct waves, is called succession, a predictable enough phenomenon for Goff to use in establishing the postmortem interval.

Goff recalls a case from November 1996 in which the body of a young woman was found in a sugar cane field on the island of Kauai. "The body was very decomposed and not a lot of physical evidence remained," he says. But using samples of insect evidence he collected, Goff estimated a postmortem interval of 34 to 36 days. "They didn't have any suspects, but they did have one individual who said he had given the lady a ride 33 days ago," he says. On the basis of Goff's information, police obtained a search warrant and searched the individual's home but found nothing suspicious. "Finally," Goff says, "they went in and sprayed luminol," a compound that glows when it binds to hemoglobin in the blood. After police sprayed the house, the outline of a body was clearly visible on the floor of the bedroom. There were traces of blood in other rooms too, left when the suspect dragged the body through the house to his car. "The trunk of his car just glowed," Goff says.

During the trial, the jury heard the entomological evidence despite the defense attorney's efforts to suppress Goff's findings, query the validity of the search warrant and discount the luminol evidence. The suspect was found guilty of murder. As with many other cases, this one probably would have been solved in time. "But it's a matter of when it would have been solved," Goff says.

Next Page: Goff's research may sound like bad news for pigs

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