In 1986 Crimewatch made appeals on three separate murders. Now with special access to police records Crimewatch File reconstructs the inside story of a major police investigation. Between December 1985 and May 1986 three young women - Alison Day , Maartje Tamboezer and Anne Lock - were raped and murdered. At first the cases seemed quite separate, but definite links soon emerged. Then police discovered another connection - to 27 rapes in North London. The investigation involved four police forces and over a million hours of inquiries, until tiny but crucial clues took them to the home of a 28-year-old unemployed carpenter from Kilburn.