The story of how double-murderer Colin Pitchfork became the first criminal to be snared by DNA fingerprinting. In the mid-1980s, Pitchfork raped and killed two Leicestershire schoolgirls, but despite exhaustive investigations evaded capture, largely due to a false confession and a bogus blood test which threw police off his scent until a chance remark in a pub redirected them to the true perpetrator of the crimes