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.