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.