Pigs at sea reveal latest clues in homicide research

July 23, 2000

The bodies of homicide victims found at sea or washed up on shore could provide investigators with crucial information needed to help solve the crimes -- once the activity of the animals that infest them under water is more clearly understood.

That's why Simon Fraser University forensic entomologist Gail Anderson is keenly watching what happens to six pig carcasses that she has dropped and anchored in Howe Sound off Bowen Island, near Vancouver.

Anderson's expertise on insect activity on homicide victims allows her to pinpoint with great accuracy such details as time of death and whether a body has been moved. She's taking the research to new depths because murders that involve bodies found in water can be among the toughest to solve.

"There is often nothing on which an investigator can pin evidence, yet there exists a wealth of information in the form of the sea creatures and the activity that occurs while a body is immersed," says Anderson, a professor in SFU's school of criminology, who is frequently called on to help investigators at crime scenes and to share her expertise in court.

Anderson's latest work is being funded by the Canadian Police Research Centre in Ottawa and has drawn a wealth of supporters from the Vancouver Aquarium, the RCMP and the Canadian Coast Guard. All are supplying divers as well as boats and underwater recording equipment.

The pig carcasses were dropped in late May, each weighted with three cinder blocks connected by a chain and dropped several thousand metres apart, to levels of 25-50 metres. Since they were dropped Anderson and dive crews have been out to sea about a dozen times.

Her initial results show significant promise. "We're seeing a wide range of things happening in the underwater environment, " says Anderson, who relies on divers to record activity and collect species for later analysis.

During a recent site visit, Coast Guard divers found the sunken carcasses re-floating. Anderson had expected that to occur sooner. Divers also found few signs of sea life around the decomposing pigs, though a lone harbour seal hovered near one of the carcasses. Previous dives have turned up a wide variety of species, from hundreds of sea stars to small and large amphipods.

Divers on this visit report bite marks, missing body parts and what Anderson suggests could be the early onset of adipocere, at which stage body parts affected become crumbly, almost resembling cottage cheese.

Anderson says it usually takes about three months for the condition to appear, yet there are signs of it on one of the pigs. Predators lose interest in feeding on spots where the condition occurs.

"Every dive is telling us something new," says Anderson. "Once we learn what kind of activity is taking place we can begin to discover what clues that activity can provide."

Tracking the pigs' conditions depends on the availability of boats and volunteer divers. Anderson says she's getting phenomenal help. "There's a real variety of experience and approach. The RMCP and Coast Guard are more likely to notice decompositional changes, while the aquarium divers, who can quickly identify unknown species, immediately focus on the biology. The result is a well-rounded view of what's happening to these pigs."

Coast Guard diver Tim MacFarlane is enthusiastic about his involvement. "We come across a lot of people in the water, and this research will give us a greater understanding of what to look for," he says. "It's an opportunity to have a role in a breakthrough in science."

Anderson's earlier research -- targeting insects on pig carcasses buried or dropped on land at sites throughout B.C. -- resulted in the creation of the first provincial data base of insects and their activity. She is now working on a national data base of bug-colonization patterns to help investigators working in various geographic and climatic conditions. More pig carcasses were recently dropped in the Prairies as that research continues.

"I am frequently asked about what happens when bodies are found in water, so it was a natural next step in my research," says Anderson, who has been planning the marine phase for four years. She plans to create an index species and database similar to those produced through her other research. One of her former graduate students earlier conducted similar research in freshwater conditions.

Anderson will drop more pig carcasses into the sea this fall to compare climatic conditions. She hopes to incorporate findings from her marine research into a training video she recently produced for the RCMP on the collection of important species.

Anderson is setting up North America's first forensic entomology lab at SFU. This summer, she is teaching a new course that she developed called the Biological Explanations of Crime.

In August, Anderson will address the International Congress of Entomology in Brazil, and teach insect collection techniques to investigators at the Canadian Police College in Ottawa.
CONTACT: Gail Anderson, 604-291-3589, or ganderso@sfu.ca
Marianne Meadahl/Julie Ovenell Carter, media/pr, 04-291-4323

Simon Fraser University

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