Peter Sutcliffe hammered 20 year old Jean Jordan to death near a cemetery in Manchester, then realised the brand new £5 note he had just paid her was traceable straight back to his wage packet. Nine days later he returned in the dark to retrieve it, could not find it, and instead mutilated her body and attempted to cut off her head.
The note had been lying just outside the police search area the whole time, in her handbag under a fence. Detectives traced it to a Bradford pay run and interviewed thousands of workers, including Sutcliffe himself, twice. His alibi held, the inquiry stalled, and the man holding the incriminating fiver walked free for years before he was finally caught as the Yorkshire Ripper.
