Episode one looks at one of the most feared child murderers and sex offenders the UK has ever known: Robert Black. In 1990, Black was serving a life sentence in Saughton Prison, Scotland, for the attempted abduction of a 9-year-old school girl, but was also suspected of having abducted and murdered other young females.

The confessions of 14-year-olds Kim Edwards and Lucas Markham reveal the shocking justifications for murdering Edwards' mother and younger sister.

After hearing the confessions of Colin Ireland, who murdered five men in two weeks, detectives have been haunted by the cold and calculating detail unlike anything they'd heard before.

When nurse Elizabeth Wettlaufer walked into a police station, she confessed to murdering eight patients with insulin, but explained that she had the ultimate motivator - God.

A confessional interview with Ted Bundy.

Nilsen murdered 15 young men whose bodies he sought to preserve as companions before dismembering their remains for disposal down the toilet.

Few killers have divided opinion like Aileen Wuornos. Having gunned down six people, she confessed, but it was not enough to save her.

Two British serial murderers killed a generation apart, but with a common goal - they killed to gain an infamy that had eluded them in normal life.

Pickton was a pig farmer who killed 49 women before feeding them to his hogs. He was caught when an undercover police officer posed as a cellmate.

Ridgway remains one of the most prolific murderers in U.S. history, even killing prostitutes while his young son waited in the back of his car.

When Becky Watts disappeared the country was anxious for her return until police find her body. Soon stories don't add up and a computer history shows that evil lies close to home.

The case of Canadian serial killer couple Karla Homolka and Paul Bernardo.

After the death of her husband, author Helen Bailey found happiness in a new partner, but when she disappears two years later, friends and family start to ask questions.

Jennifer Pan witnessed the murder of her mother and the attempted murder of her father, but when he wakes from a coma, her father has a very different story to tell.

The FBI attempt to find a killer with no victim or geographic profile, and who covers his trail with counter forensics.

Fraternal codes are used to uncover the secrets behind a murder after a body is found.

When a criminal on probation embarks on the killing spree of ex lovers, police try to get ahead of the man who will later insist he is a victim and that society are to blame.