Officers investigate the murder of Christoper Donovan by a gang of youths.

After going missing for a year and a half, many believed 14-year-old Cheyenne had run away from home. However, closer analysis revealed the tragic truth.

After finding her dead in a bathtub full of bleach, detectives narrowed down the killer from 210,000 possible suspects.

After a badly decomposed body was found in a suitcase by a railway embankment in Exeter, Police hunt for the killer with only CCTV evidence to go on.

In 1986, Detective David Baker became the first person to use DNA profiling in a criminal investigation, when looking for the killer of two young girls.

How the investigation into Phillip Inhofer at his home in Sacremento led police to a 20-year-old call girl known as Bat Girl.

How police used CCTV, eyewitness statements and a public appeal to find the killer of a 28-year old woman, found dead on Nottingham's streets

In 2002, police made a starling discovery inside a locked room in Anthony Hardy's home. This was merely a horrifying prelude for what was to come.

With no CCTV and no witnesses, detective Jon Buehler must find the person responsible for a drive-by shooting of "gentle giant" Sula Palega.

In 1981, detective Mike Southwell investigated a missing persons case that contained one of the grimmest discoveries in British police history

DNA left on a cigarette butt leads investigators to the brutal killer of 84 year-old gun enthusiast Kenneth spearman

Police painstakingly trawl through hours of cctv footage, location data and forensic evidence to find the brutal killer of a heavily pregnant woman

An unlikely informant holds the key to justice when 59 year old antique dealer michael Griffiths is targeted and brutally killed in his home

A computer at vogue magazine held the key to identifying julie clayton, an ex-cult member who'd been assaulted and murdered upon leaving

It took 18 years to identify melissa halstead after her torso was found in a Rotterdam canal. But detectives never stopped working to catch her killer.

A seemingly ordinary family man is the prime suspect when his wife, three young children and mother-in-law are brutally killed after church.

The FBI investigates when a seemingly perfect husband flees the United States following the murder of his wife and three children

Two women are killed in the 70s and their cases go cold for over 30 years, until a chilling link between the two emerges.

Detectives look back on the case of Elijah Butler,murdered four days after he married his wife-by her long-term stalker.

Detectives reflect on how they gathered evidence to charge Melanie McGuire with murder when her husband's remains were found in multiple suitcases

Shock pours through a community when a devoted mother is fatally attacked with a machete on her way to pick up her children.

The story of Garry Malone, who brutally bludgeoned his wife to death before making a bogus TV appeal for her to come home.

17-year-old Jayden Parkinson was killed by her abusive boyfriend, Ben Blakeley, who then buried her in his uncle's grave.

The chilling crimes of Colin Pitchfork, who became the first person to be convicted of rape and murder using DNA profiling.

After ending her relationship, 15-year-old Maleha Masud pays the ultimate price when her ex-boyfriend starts a lethal blaze at her home.