After a teenager is murdered in her flat, police try to find her killer, starting with a set of bloodstained keys.

The Opportunist Murder: When a woman is found dead in a hotel, police realise that an apparent suicide is not what it seems, leading to a manhunt that crosses borders.

A woman heads off on an extended honeymoon but her out-of-character contact worries her friends, resulting in a tragic discovery.

An evil web of lies and deceit confronts detectives after they discover the body of grandfather Peter McMahon in a freezer.

A murder begins a tawdry tale of stolen money, an international escape attempt and an email from the supposed killer keen to sell his story.

See how police used CCTV to trace the perpetrator of a crime that shocked the nation - the murder of teacher Sabina Nessa in London.

A student's strange disappearance becomes a murder investigation, and detectives face a tough task to prove the suspect's guilt.

The Identity Thief Killer: When a woman's body is found in a bin in Lewes, police look for the perpetrator of a disturbing crime.

Philip Glenister explores the aftermath of Bei Carter's murder in Bridlington. The investigation hinged on the public's sightings after her killer vanished.

Philip Glenister delves into the story that unfolded in the aftermath of mother-of-four Saima Khan's murder in her Luton home.

The manhunt spanned three countries when Geoff Seggie was murdered in his Derbyshire home. His killer eventually made contact, but he never revealed his motive.

Police thought Manchester mum Sian Roberts's murder was a cut-and-dried case when they got a frantic 999 call from her ex. However, they could not have been more wrong.

Police are at a loss when a 79-year-old is killed in her Hartlepool home. But when the evidence mounts and the killer's movements are tracked, the net closes in.

A look into the 2007 murder of farmer's wife Kate Prout in Gloucestershire. Having failed to find her body, police wondered if the truth would ever be revealed.

Ian Stewart murdered his partner, children's author Helen Bailey, in 2016. He dumped her and her dog in a septic tank at her Hertfordshire home, but reported her missing and produced a note claiming she had gone to stay at a holiday home.

Alarm bells ring for detectives when the hunt for Peter Fasoli's murderer leads them to a second body in Italy. Suddenly, the search is on for a serial killer.