Traces of Guilt

There will always be those who think they can commit the perfect murder. In reality it's virtually impossible to leave no evidence at the scene of a crime. Fingerprints, hair, fibres and blood can all lead to the killer. In this second episode, surgeon Gabriel Weston explores the cases that were solved by examining the smallest traces of forensic evidence, from the first murder case solved in the UK based on fingerprint evidence to the patterns of blood in a bedroom which helped overturn an infamous murder conviction.

As well as looking to the past, Gabriel investigates the cutting-edge techniques that are proving vital in catching the killers of today. Amazingly, forensic science can now detect with pinpoint accuracy where someone has walked across an area the size of Scotland, based on nothing more than the soil stuck to the sole of a suspect's shoe.