Few things are more important in forensic science than determining time of death, which is why over the years researchers have spent so much time measuring body temperatures and scrutinizing maggots.
Now, there might be a better way. A team led by Peter Steinbacher, a lecturer at the University of Salzburg, has developed a technique that they say will be accurate for up to ten days after death, a vast improvement over current methods.
The current state-of-the-art technique measures core body temperature. It takes anywhere between one to two days for a deceased person’s core body temp to equilibrate with the surrounding environment. In general, a body loses about 2.7˚ F for every hour. Water, ice, or extreme heat or cold can change that equation.
But Steinbacher and team’s method doesn’t rely on temperature, Instead, it analyzes changes to muscle proteins. After a person dies, their muscles begin to decay. The researchers found that five proteins sampled from the quadricep and hamstring—desmin, troponin t, tropomyosin, m-calpain, and μ-calpain, in case you’re curious—all degraded in a reliable and predictable fashion. Based on the amount of these proteins and the products into which they degrade, Steinbacher and his team were able to estimate time of death up to ten days post mortem.
There’s still more work to be done, though. Here’s Victorial Gill, reporting for BBC News:
“We now need more samples to find out whether gender, body mass index, temperature, humidity, etc play a role in the time-course of muscle breakdown,” said Dr Steinbacher.
It will be at least a few years before the muscle protein technique can be used in the field, though, in part because most of the research was done using pig muscles, which are similar to humans but not perfect copies. Further studies using human donors will help eliminate any uncertainties.