There’s been a murder. You’ve been called to the scene of the crime to determine cause and time of death and to collect whatever evidence you can find… Where do you start?

A dead body can yield many clues. One of the first things to test for is the presence of alcohol, drugs and poisons (Napoleon’s hair showed arsenic, for example) in the body – these are identified during a toxicology examination.

The body’s state of decomposition can indicate the time of death. This is usually easy to estimate within 12 to 24 hours of death, any later investigators has to use indirect evidence such as chemical signatures or insect colonisers like blowfly maggots or flesh-eating beetles (Hope you’re not planning on having lunch soon).

These methods aren’t always that accurate and new methods are being researched by studying the decomposition of pig and human corpses. In the case if burn victims, radioisotopes can be used to determine time of death.