Cracking the case with bugs

ONLY IN THE PAST 10 years has forensic entomology become a common investigative tool. The King County medical examiner makes good use of his expert on insects.

The gurney rolls out of the morgue cooler, and Monty Nelson can't wait for a peek.

But as human remains recently found in the woods come into full view from inside the green body bag, Nelson doesn't dwell on signs that make police call the death "suspicious."

Instead, he combs through the folds of the dead man's faded navy parka and sifts through the soil that's collected at the bottom of the body bag. He's in search of what to him is the ultimate evidence: insect pupae, little brown cocoons that look like embryonic pine cones, that reveal secrets about what happened.

Nelson brings the King County Medical Examiner's Office a specialty it hasn't had at least since the 1980s: forensic entomology, the art of solving deaths by looking at bugs. Hired two years ago as a death investigator, Nelson quickly became known for his knowledge of bugs and gradually evolved into the county's forensic-entomology expert.

Forensic entomology has been around for half a century, but only in the past 10 years has it emerged as a commonly used investigative tool, says Jason Byrd of Virginia, one of only nine forensic entomologists in the country.

"Before, investigators used to spray Raid and wash the body to get rid of the bugs," he says. "Now, they collect them, just like they would do dusting for fingerprints."

It works like this: Insects lay eggs, which hatch, become maggots, dine and make cocoons. They grow to adults, hatch and fly away in search of a new food source.

By determining their species, entomologists can make inferences about the conditions in which someone died. For example, bluebottle flies are generally present in cooler weather, while greenbottles don't arrive until May, helping to narrow down the season of death.

How insects colonize a body also can say a lot. They can indicate a gunshot wound or sexual assault and help determine whether a body has been stored indoors and then moved outdoors.

It's also possible to analyze the cocoon for traces to see if the deceased ingested chemicals or drugs.

On a recent day, Nelson stood near the autopsy table as forensic anthropologist Kathy Taylor examined the body. "He's got good bugs. Check it out," she says, showing Nelson a few.

She won't say where the body was found or by whom, revealing only that the death does not appear to be from natural causes and that the victim may have been dead six months to five years.

"Once you go skeletal, the bones could be around for a long time," Taylor explains.

The details will come later. First Nelson has to do his work. He'll collect the cocoon samples and send them to a forensic entomologist in Virginia, who will analyze them to determine how long the man has been dead. "The bugs give us little hints," he says.

Nelson, 37, who studied archaeology, worked as an emergency medical technician and spent seven years selling tents at REI, has now made himself into a forensic-entomology specialist.

Make that a fanatic.

"These are the maggot cocoons. They're really lovely. Just look at their structure," he says as he clicks through a set of slides showing the varying stages of maggot infestation.

Since entomologists can't get to every death scene, the Medical Examiner's Office has trained investigators such as Nelson to collect the samples at the morgue and record the data.

Medical Examiner Richard Harruff has sent Nelson to classes, workshops and even the University of Tennessee Anthropological Research Facility, known as the "Body Farm," where scientists study decomposition rates.

For Nelson it was fascinating. At home, he raises maggots. He likes to watch them develop. To attract them, he places a piece of beef liver in his back yard, covered with a cage to keep his border collie away. "For those of us interested in natural history, we get beyond the icky," he says, defending his hobby.

Nelson is "probably one of the best-trained death investigators in the country," says Byrd, who teaches criminal justice at Virginia Commonwealth University in Richmond. "He has been really progressive."

Court cases where findings based on bugs play an important role in the time of death come up maybe once a year, Harruff says. Yet the office regularly uses entomology as part of its toolbox of investigative techniques to answer other questions.

Understanding the cool logic of insects is only part of Nelson's job, one that requires him to systematically extract facts from chaotic death scenes. The rest is full of raw, human emotion.

He's the person who knocks on front doors to tell people their loved ones have died.

He shows them a face of dignity and character, so they can search his blue eyes, framed by metal glasses, and know he is telling the truth. They look at his lined forehead and watch his neat mustache move ever so slowly as he speaks such words as, "I'm sorry, but I have to tell you your son died in a car accident today," in his earnest Minnesota voice.

The job does touch him. It often happens when he sees a victim who looks like one of his children, who are 5 and 10.

"It's just overpowering," he says, his normally peppy voice straining. "I'm the guy who moves her and swaddles her and puts her in the clean white sheets and holds her hand for fingerprinting."

Sometimes the job weighs heavily, and at other times, he worries about becoming too blase, forgetting that death is about the loss of a human being.

"I'm sitting here like it's normal. That's when it's time to take a walk in the woods."

It's quiet there, and he likes to look at the bugs.