The gripping series returns with the case of a multi-generation murder in Wales. It took years to bring the killer to justice - had they been hiding within the police's own ranks?

After 19-year-old Cassandra McDermott is found dead in her home, her family endure a cruel waiting game as their only hope for justice is if the murderer tries to kill again.

Stefan Kiszko was convicted of murder when 11-year-old Lesley Molseed was found dead on the Yorkshire Moors. Sixteen years later he was declared innocent, so who did kill Lesley?

When 77-year-old Georgina Edmonds is murdered in her Hampshire cottage, the community believes the killer must be an outsider, but the police are baffled by a series of dead ends.

The sadistic murder of Wendy Speakes shocked the city of Wakefield, with evidence suggesting that a man with a twisted fetish was on the loose and could kill again.