World's Most Evil Killers

Diane & Rachel Staudte: A mother poisons her family with antifreeze, killing her husband and son, until a tip sparks an investigation that exposes Diane Staudte's crimes. (S10, ep 10)

Diane & Rachel Staudte: A mother poisons her family with antifreeze, killing her husband and son, until a tip sparks an investigation that exposes Diane Staudte's crimes. (S10, ep 10)

John Eric Armstrong: In 1999 and 2000, John Eric Armstrong prowled Detroit looking for sex workers. A seemingly normal father, no one suspected he was a killer. (S8, ep 3)

Richard Biegenwald: Over a 25-year career of murder, Richard Biegenwald killed at least six people as he sought out ever more inventive ways of dealing death. (S8, ep 4)

Richard Biegenwald: Over a 25-year career of murder, Richard Biegenwald killed at least six people as he sought out ever more inventive ways of dealing death. (S8, ep 4)

Christopher Hightower: A profile of the Rhode Island family man and Sunday school teacher, who also turned out to be a cold-blooded triple murderer.

Christopher Hightower: A profile of the Rhode Island family man and Sunday school teacher, who also turned out to be a cold-blooded triple murderer.

Charles Ng And Leonard Lake: The chilling case of a Hong Kong kleptomaniac and a Vietnam veteran who committed a series of horrific murders from their cabin in California.

Charles Ng And Leonard Lake: The chilling case of a Hong Kong kleptomaniac and a Vietnam veteran who committed a series of horrific murders from their cabin in California.

Richard Biegenwald: Over a 25-year career of murder, Richard Biegenwald killed at least six people as he sought out ever more inventive ways of dealing death. (S8, ep 4)

Richard Biegenwald: Over a 25-year career of murder, Richard Biegenwald killed at least six people as he sought out ever more inventive ways of dealing death. (S8, ep 4)

Angel Maturino Resendiz: Known as The Railroad Killer to some, the serial killer is thought to have taken the lives of more than 23 victims before his execution in 2006.

Angel Maturino Resendiz: Known as The Railroad Killer to some, the serial killer is thought to have taken the lives of more than 23 victims before his execution in 2006.

Cary Stayner: Also known as the Yosemite Park Killer, Cary Stayner murdered four women in 1999 before his capture. Were his actions the result of a tragic childhood?

Cary Stayner: Also known as the Yosemite Park Killer, Cary Stayner murdered four women in 1999 before his capture. Were his actions the result of a tragic childhood?

Richard Kuklinski: For Richard Kuklinski, crime was his way of life. As a professional murderer, his unusual methods led to a disturbing nickname, The Iceman. (S8, ep 5)

Richard Kuklinski: For Richard Kuklinski, crime was his way of life. As a professional murderer, his unusual methods led to a disturbing nickname, The Iceman. (S8, ep 5)

William Suff: A profile of the murderer known to some as the Riverside Prostitute Killer, who sits on death row after being convicted for the slaying of 12 women.

William Suff: A profile of the murderer known to some as the Riverside Prostitute Killer, who sits on death row after being convicted for the slaying of 12 women.

Richard Paul White: When police in Colorado interrogated Richard Paul White about the murder of his friend, he began confessing to even more horrifying crimes. (S1, ep 6)

Richard Paul White: When police in Colorado interrogated Richard Paul White about the murder of his friend, he began confessing to even more horrifying crimes. (S1, ep 6)

Todd Christopher Kohlhepp: A chilling profile of the vicious serial killer who claimed the lives of at least seven innocent people between 2003 and 2016.

Todd Christopher Kohlhepp: A chilling profile of the vicious serial killer who claimed the lives of at least seven innocent people between 2003 and 2016.

Michael Bruce Ross: An in-depth look at the life and crimes of Michael Bruce Ross who was executed in 2005 after murdering eight women across Connecticut and New York. (S9, ep 3)

...Most Evil Killers. Rodney Alcala: Examining the murderer who appeared on a dating game show in the midst of a killing spree that may have claimed as many as 130 victims.

...Most Evil Killers. Rodney Alcala: Examining the murderer who appeared on a dating game show in the midst of a killing spree that may have claimed as many as 130 victims.

Billy Mansfield Jr: Billy Mansfield Jr murdered at least five victims, but investigators suspect the extent of his serial killing is still to be revealed. (S8, ep 7)

Billy Mansfield Jr: Billy Mansfield Jr murdered at least five victims, but investigators suspect the extent of his serial killing is still to be revealed. (S8, ep 7)

Daniel Lee Siebert: A look at the life of the American serial killer, who was convicted of three murders but confessed to many more.

Daniel Lee Siebert: A look at the life of the American serial killer, who was convicted of three murders but confessed to many more.

Wolfgang / Beate Schmidt: The case of "The Pink Giant", Wolfgang Schmidt (later Beate), a transgender German serial killer who brutally murdered five women and an infant.

Wolfgang / Beate Schmidt: The case of "The Pink Giant", Wolfgang Schmidt (later Beate), a transgender German serial killer who brutally murdered five women and an infant.

Daniel Lee Siebert: A look at the life of the American serial killer, who was convicted of three murders but confessed to many more.

Sante And Kenneth Kimes: An investigation into the murderous mother-and-son duo, who killed their elderly landlady in a greed-fuelled ploy.

Sante And Kenneth Kimes: An investigation into the murderous mother-and-son duo, who killed their elderly landlady in a greed-fuelled ploy.

Karol Kot: A look at the life of the Polish serial killer, nicknamed the Vampire of Krakow for his wildly varying choice of victims, from young children to the elderly.

Karol Kot: A look at the life of the Polish serial killer, nicknamed the Vampire of Krakow for his wildly varying choice of victims, from young children to the elderly.