Watch Robbie Coltrane's Critical Evidence

A missing person's investigation that quickly turned into a hunt for a killer--but with no body, how could police prove murder?

A double axe murderer and no clues--except tiny flakes of paint discovered deep in the wounds of one of the victims. This is a story of how forensic science--and the determination of one detective--found the killer.

In 1973 three young girls were beaten, raped and strangled over a six-week period. The SaturdayNight Strangler escaped justice for almost 30 years. But new techniques in DNA technology and amidnight exhumation finally uncovered the killer.

Landlord Kyu Soo Kim created a web of lies and misdirection to try and cover the fact he had bound and suffocated two of his tenants after extracting their PIN numbers. But police had some key witnesses to his crimes--flies.

A murder and an attempted murder at a farmhouse in an idyllic village deep in the Cotswolds. When police discovered the truth about what happened, they were horrified.

A teenager went for an interview for the job of her dreams and was never seen alive again. But a bite mark found on the chin of 17-year-old Lynne Rogers led police to her killer.

Murder by chloroform is extremely rare. But this wasn't a plot from a detective novel--it was the cold blooded murder of Sameena Imam at the hands of the person she loved.

An old carpet dug up by workmen in a back garden in Cardiff in 1989 was the beginning of a case that would push the boundaries of forensic science.