Host Donnie Wahlberg chronicles the dark and twisted lives of an array of diabolical criminals, such as Charles Manson, Aileen Wuornos, John Wayne Gacy, the Rev Jim Jones, and many others.
The Ken and Barbie Killers - Dead Ringer Part 1: From 1987-1992, Ontario authorities join the FBI's hunt for the monster responsible for a horrific crime spree. (S4, ep 1)
The Ken and Barbie Killers - I Kidnapped a Girl Part 2: A tip points to an unlikely suspect - a blonde, blue-eyed accountant who lives with his wife in the suburbs. (S1, ep 2)
Back to School Killer Part 1: When college-aged women in Charlottesville start going missing, the search for answers leads authorities to local star athlete Jesse Matthew Jr. (S4, ep 3)
Back to School Killer Part 2: Clues point to Jesse Matthew Jr when women disappear in Charlottesville. Two women are killed, but one survives to bring the murderer to justice. (S4, ep 4)
Sammy 'The Bull' Gravano Part 1: Sammy 'The Bull' Gravano was the right-hand man to mafia kingpin, John Gotti, carrying out multiple murders. (S4, ep 5)
Sammy 'The Bull' Gravano Part 2: After his arrest, Gravano broke the sacred oath of silence and cut a deal with the government, testifying against his former boss. (S1, ep 6)
The Hillside Stranglers - A Pair of Serial Killers Part 1: In 1977, bodies of young women begin piling up in LA - all of them nude and showing signs of torture. (S4, ep 7)
The Hillside Stranglers - She Walked Into the Trap Part 2: A year after the bodies of nude women began piling up in LA, two murders uncover the Hillside Stranglers. (S4, ep 8)
Cross Country Killer Part 1: Samantha Koenig was closing shop in Anchorage, when a man known in the community as a business owner kidnapped her - leading to an intense manhunt. (S4, ep 9)
Cross Country Killer Part 2: Samantha Koenig was closing shop in Anchorage, when a man known in the community as a business owner kidnapped her - leading to an intense manhunt. (S4, ep 10)
John Gotti - It Was Kill or Be Killed Part 1: John Gotti earned the name Dapper Don, but in reality, he was a ruthless gangster who ordered hits on enemies and friends alike. (S4, ep 11)
John Gotti - There Were Fatal Consequences Part 2: John Gotti earned the name Dapper Don, but he was a ruthless gangster who ordered hits on enemies and friends alike. (S4, ep 12)