After two young girls were killed, a mishandled prosecution ended in a murderer walking free until a later, more dedicated investigation brought him to justice.
A missing girl's parents insisted she had just run off with a boy, but detectives persisted and gradually unearthed a sick story of toxic family relationships.
Soon after the corpses of two teens were found, a decades-spanning investigation began, with officers labouring for years to bring the killers to justice.
After a woman disappears, an investigation identifies the likely culprit to be her boyfriend, but despite years of effort he receives only a light sentence.
After a mother finds her son's dead body at his home, detectives begin a lengthy and complicated investigation centred around good old fashioned policework.
When a man was suddenly stabbed to death by a stranger one night in 1994, authorities began three decades of relentless police-work to discover the culprit.
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?
On the tenth anniversary of Vikki Thompson's brutal murder in the Thames Valley, a new lead emerges that results in the case being re-opened
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.
How it took 14 years to bring Shamsuddin Mahmood's killer to justice.
A small fleck of paint becomes a lead to finding the killer who murdered Doctor Brenda Page fourty years ago.
The stories behind famous cold case murder investigations.
Ten years after local Cardiff girl Geraldine's body was found a few days before Christmas, Detective Superintendent Paul Kemp and his team set out to catch the culprit with new groundbreaking forensic science. However, when they get a DNA match to a suspect they must act fast as he is about to be released from Dartmoor Prison.
Thirty years after her murder, could changed loyalties help find Sally McGrath's killer?
In 1979, 22-year-old Teresa de Simone is found murdered in the back of her car. Sean Hodgson is found guilty and sentenced to life but hopes that new DNA technology will clear his name.
Investigating the murder case of Samo Paul and Tracey Turner from the 1990s. In 1997 former Chief constable Mick Creedon and his team in Leicester announced that the cold case murders are the work of one man- a serial sexual predator who is still out there. Creedon uses the DNA in an attempt to catch the killer before he strikes again.
Following the murder case of 26-year-old Surjit Athwal, who failed to come home to London from a family trip to India in the December of 1998. Her husband and mother-in-law returned without her claiming that Surjit changed her travel plans, however Surjit's brother Jagdeesh reported her as a missing person to the police. Law enforcement faced a wall of silence from the tight knit Sikh community. A women who knew what had happened to Surjit feared she would be the next to disappear if she chose to reveal the truth.