Gil Grissom and his CSI team are not the only investigators solving crimes using bugs as timestamps.

Homicide investigators sometimes rely on insects to determine the length of time since a victim’s death. This approach, however, has limitations.

One sector of research that Clifton Bishop is finding a molecular approach to estimate times of deaths. Bishop, associate professor in the Department of Biology at West Virginia University, uses RNA molecules to obtain such information.

Currently, a principal way to estimate a person’s time of death is through forensic entomology. In other words, time is factored based on insect presence and activity in and around the body. Investigators also assess the state of development those insects have reached.

Bishop said one of the disadvantages of forensic entomology is that insects sometimes do not have access to the bodies. Insects may even be inactive or absent in these environments, making it challenging for forensic entomologists to determine a time of death.

Another problem with this method is that, eventually, the flesh will be completely consumed. When the food source is gone, the insects leave. This makes time of death estimates even more difficult.

Bishop is researching a molecular approach, which could triple the length of time an estimate could be made. This method would be largely independent of environmental conditions and insects.

“If there someone was in a freezer or impermeable body bag for weeks, this method would still work,” Bishop said.

Stephanie Young, a fifth-year doctoral candidate in biology, works in Bishop’s research group. Young said she never thought she would be working in this unusual area of biology when she first entered school, but she loves it.

“This could really help someone,” she said. “It could exonerate a wrongfully accused person or help reconstruct events associated with a murder.”

Bishop and Young are also researching the creation of a portable crime lab to process forensic evidence. Bishop has studied the amount of time it takes a crime lab to process DNA and other evidence collected at a crime scene. He says initial tests at crime scenes are presumptive and provide only partial information regarding the source of a stain. Since DNA evidence is used in most criminal cases, there is a high backlog of samples in crime labs across the country.

“We are trying to reduce the backlog of these samples by creating a portable crime lab, so the conclusive tests on the origins of stains could be performed at the crime scene, allowing investigators to determine which samples should be collected and processed for DNA analysis and not collect those of no value,” Bishop said. “Giving investigators better access to quick accurate lab results can be critical in assisting in solving a case.”

This research is funded by the U.S. Department of Justice.


jh 5/27/11

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