Messenger - Vol. 2, No. 1, Page 29
Fall 1992
Alumni Profile; Six-legged informers help solve homicides

     Within minutes of a murder, the first wave of tiny telltales arrives
on the crime scene.
     Once considered disgusting companions to a corpse, these
witnesses-flies, maggots, beetles and moths- always arrive in a predictable
pattern over a period of time. And, in the hands of a forensic entomologist
such as E. Paul Catts, Delaware '52, MS '57, the insects can provide the
necessary clues to crack the case.
     Catts is a professor of entomology at Washington State University.
Along with a couple of dozen other entomologists across the nation, he uses
insect evidence to help solve crimes. Insects can't name the victim or find
the suspects, but their presence or absence can tell detectives when a
person died, if a body has been moved and whether the victim was killed
indoors or out, at day or night or in warm or cool weather.
     According to Catts, there are four waves of insects that are most
useful to criminal investigators. First on the crime scene are blowflies,
appearing within one to five minutes after death. This first wave, which
includes yellow jackets and ants, will continue to appear for about three
days during the warmer seasons. Within 30 minutes of their arrival, the
flies lay eggs that will turn into maggots. Maggots also have predictable
growth stages and even their pupae can be dated by forensic entomologists.
     The second wave are tiny flies, some the size of pin heads, known as
the scavenger fly and the dung fly. Rove beetles and their companions-the
carrion and hister beetles- make up the third wave. The fourth wave
consists of hide beetles, mites and certain moths.
     "If the body is discovered the first week, we can estimate the time of
death within 12-24 hours," Catts says. "By the second week, our accuracy is
within 1 or 2 days. By a month, we can predict the time of death within 3
to 5 days."
     Because the insect invasion sequence is so predictable and because
most flies don't roam far from where they hatched, the presence of larvae
of dramatically different ages or subspecies may indicate that the victim
was killed in one place and then transported to another. Sometimes, just
knowing the time of death from insect evidence will place the victim in the
company of a murder suspect.
     Catts has been involved in the investigation of more than 50
homicides. He says his most interesting case occurred in 1989 when he was
giving a seminar in Tennessee with a fellow forensic entomologist.
     "The police asked us to consult on a Jane Doe whose skeletal remains
had been discovered in the Cumberland Mountains," he says. "All that was
found was a skull, a few cloth pieces from a pair of jeans and some
disarticulated (disjointed) bones. The skull was sitting in leaf debris,
and a paperwasp nest was found in an opening in the back.
     "We decided since this wasp looks for a dry, protected place for a
nest, the skull had to have been dry during the previous spring. When we
found some pupal cases of the small flies from the second wave of insects,
we knew the first wave of blowflies was complete.
     "Then we checked meteorological data to determine how late the
blowflies had been out the previous fall. All our evidence indicated that
the individual had been dead about 17-1/2 months."
     This estimate was confirmed by a materials specialist, who dated the
blue jean fragments, and a physical anthropologist, who said the weathering
on the skull indicated it had been outside about 18 months. "These
conclusions allowed the police to look at the missing persons report from
1987," Catts says, "and they ultimately identified the victim from dental
records as a 15-year-old runaway."
     A classic "locked room" murder in Tacoma, Wash., was solved with
assistance by Catts two years ago. According to an account in the Wall
Street Journal, police had found the decomposing body of a 34-year-old man
tangled in his bed clothes with a bullet in the neck. The doors and windows
were fastened from the inside, and although the man's gun lay on a dresser,
it hadn't been fired.
     Investigators scooped up a handful of maggots and sent them to Catts.
He found that two generations of blowflies had hatched at the scene. Since
it takes three weeks for a generation to become adults, Catts estimated
that the body had been in the room at least seven weeks. Police detectives
found a neighborhood party had been held about that time and a reveler had
fired off several shots. The path of one bullet, the police then
discovered, led from the victim's bed back to the party house.
     The party-goer pleaded guilty to manslaughter and received a 27-month
     Although Catts consults on 12-15 criminal cases a year, his major
research interest has long been livestock losses caused by bot flies.
     These flies invade living creatures and infest them with maggots.
After completing his doctorate at the University of California at Berkeley,
Catts returned to Delaware where he taught in the Department of Entomology
from 1962-80.
     Catts became more seriously involved in criminal investigations when
police in Washington began to call on him. He says he and the other 20
forensic entomologists in North America usually collaborate on cases, which
have involved murders and mysterious deaths from Florida to Canada. "We
always run our analyses by each other," he says.
     Currently, Catts is consulting on the serial murders of prostitutes in
Spokane. Although he doesn't visit crime scenes, he considers the real role
of a forensic entomologist to train investigators on what to look for.
"They have to know what to collect," he says. "In the most recent case,
they did an excellent job, sweeping insects off the leaves around the
     He also is directing the research of a master's candidate who is
studying the development rate of black blowflies collected from four
different geographic areas of the U.S. By pinning down such variables,
Catts says he hopes to give criminal investigators even more accurate
estimates on the date of death.
     Catts and several of his colleagues have written a 182-page book
titled Entomology and Death. Not intended for the squeamish, the manual of
forensic entomology findings and procedures has only sold a few hundred
     But it received rave reviews in one publication-the FBI's Law
Enforcement Bulletin.
                                   -Cornelia Weil