Some cases are open and shut. Others present as a complete mystery, and it takes an Expert Witness to uncover the first clues. That’s what happened when human remains were discovered in an abandoned sports bag in Sheffield. Detectives were stumped, until a team of expert witnesses using the most unlikely evidence helped them crack the case.

The programme's second case is based in Bradford where a DNA scientist examines 25-year-old evidence, to solve a murder cold case. DNA profiling has revolutionised how police investigate cold cases. Detectives can use it to identify suspects and crack investigations once thought impossible to solve - but only if scientists are able to find the DNA in the first place and sometimes that can be a real challenge. Show less