In 1985 the flying squad was looking for a gang of armed robbers who were strapping remote-controlled explosive devices to their victims. A 14-year-old saw Crimewatch and gave police information they could scarcely believe. It led to eight months surveillance, threw up the names of some notorious London criminals and led to the arrest of the gang. The case made criminal history when one of the robbers, Donald Barrett , turned supergrass for the second time. The handling of a double supergrass posed new problems for the officers close to Barrett and to those in charge of the investigation.

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.

Crimewatch File reconstructs the inside story of a major police investigation. A uniformed police officer is shot dead during a routine enquiry in the centre of Leeds and police face an apparently motiveless crime. The killer leaves few clues. Not since the 'Ripper' murders have West Yorkshire police been confronted with such a massive enquiry. The investigation involved four police forces, and reached its unexpected and dramatic climax two-and-a-half years later.