In 2010, Derek Bird took his gun and, in less than twenty-four hours, killed twelve people and injured eleven more. He stopped when he had run out of ammunition, finally turning the gun on himself.
Over six years, a copycat Zodiac killer stalked the streets of New York City in search of easy targets.
Billy Dunlop killed Julie Hogg in 1989 but was acquitted after two failed trials. However, due to a change in the UK law in 2005, Dunlop was finally convicted and sentenced to seventeen years in prison.
By the age of nineteen, Polish schoolboy Karol Kot, aka the Vampire of Krokow, had killed two people. He tried to kill many more in arson and poison attempts and was executed at the age of twenty-one.
A master manipulator accused of his wife's murder is eventually caught by a polygraph test.
Between 1989 and 1992 in East Germany, Wolfgang Schmidt, known as the Beast of Beelitz, murdered four women and a baby.
In 1987, Michael Ryan went on a killing spree in the quiet market town of Hungerford in Berkshirem before turning the gun on himself.
Billy Mansfield Jr. moved between Florida and Michigan, targeting vulnerable women and girls.
Jorge Torrez was a prolific predator capable of carrying out heinous and horrific acts.
In 2010, bodybuilder Raoul Moat shot his ex-girlfriend and her partner, and went on the run and declared war on Northumbria police, vowing not to stop killing officers until he was dead.
Dublin man Eric Locke refused to accept it when Sonia Blount, a mother of one, ended their relationship.
Stephen Griffiths, the self-proclaimed Crossbow Cannibal, had always fantasized about murder. In 2009, he acted on his murderous instincts and killed three women.
In December 2015, Horst Kroner boarded a plane. He had brutally murdered his wife while she slept and was now headed to Thailand for easy sex.
Rapist Arthur Hutchinson escaped from police custody in October 1983. Whilst on the run, he broke into the Laitners' house in Dore, Yorkshire and murdered three family members.
Railway Killers John Duffy and David Mulcahy killed three women and raped many more across a four-year period in the early 1980s.
Keith Jesperson, known as the 'Smiley Face Killer,' brutally killed at least eight women across five American states in the early 1990s.
Thierry Paulin murdered 21 elderly women during the 1980s. He lived a lavish lifestyle, funded by the money stolen from his victims.
Ian Huntley abducted two ten-year-old schoolgirls, Holly Wells and Jessica Chapman, murdered them and tried to burn the bodies.
A look into the case of a sadistic killer, who posed as an MI5 agent in order to torture and murder his victim during a bondage sex session.
Thierry Paulin murdered 21 elderly women during the 1980s. He lived a lavish lifestyle, funded by the money stolen from his victims.