Forensic investigations may be possible 10 days after death with new method – study

AFP PHoto / Scott Olson
Forensic experts will soon be able to determine an exact time of death for victims even after a span of 10 days thanks to a new method developed by Austrian researchers.

A new technique for calculating time of death that may substantially extend the time window for forensic investigations has been developed by a group of researchers from the University of Salzburg in Austria led by Peter Steinbacher.

The group’s findings were published in the International Journal of Legal Medicine and presented on July 2. 2015 at the meeting of the Society for Experimental Biology.

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Determining time of death is one of the most important aspects of forensic studies. It is conducted using several methods including measuring body temperature, degree of rigor mortis, and decomposition. However, all of these methods only work until the body reaches ambient temperature, meaning that forensics analysts have only about 36 hours to determine TOD after a person dies.

The new method could provide a reliable TOD estimation up to 200 hours longer than earlier possible – up to 10 days after death.

The method is based on measuring the degradation of muscle proteins over the course of time. The scientists conducted experiments on dead pigs, observing how different proteins in the pigs’ hind limbs degraded at 6 hour intervals for 10 days.

They found that the process of degradation for different proteins and enzymes always followed the same timeline, with each proteic substance decaying according to a specific predictable timetable. They also determined that some of the proteins analyzed only started to degrade after 240 hours.

“It is highly likely that all muscle proteins undergo detectable changes at a certain point in time, and this would extend the currently analyzed timeframe even further,” says Dr. Peter Steinbacher, the scientist and a biologist leading the study at the University of Salzburg.

National Laboratory Center in Beltsville, Maryland .(Reuters / Gary Cameron)

“We have found indications that these muscle proteins degraded always in the same fashion,” Dr. Steinbacher adds. “If this would also be true for humans, then this would be a good molecular clock for the time since death.”

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Knowing that specific enzymes begin to degrade after a fixed amount of time following death and studying the timing of the appearance of byproducts from these proteins’ degradation would allow scientists and criminologists to calculate an approximate time of death.

Although the current research was based only on experiments on pigs, the team has already started tests on human samples with “promising” preliminary results.

“We were able to detect similar changes and exactly the same degradation products in human muscle tissue as we had in our pig study,” says Steinbacher.

“Our new and preliminary data on human samples also show that the same breakdown products are present in humans… this is of course very promising!” he added.

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Apart from the extension of the time window for determining TOD, the new method could greatly aid modern post-mortem studies, making them less complicated and time-consuming.

Muscle tissue is the most abundant in the human body, so it can be easily and quickly sampled for muscle proteins well-known to scientists. The method itself is rather simple, so results can be delivered within a day.

The research findings have already received positive feedback from academic circles, although the method presented by the research team is not likely to become commonly used anytime soon.

“There is so much riding on the time of death in many murders that we will all as a forensic and legal community have to be very convinced that there are no confounding factors before we start relying on this to convict someone,” Dr. Stuart Hamilton, a forensic pathologist from the University of Leicester, was quoted as saying by BBC.