Season 4

The "Tourniquet Killer" terrorizes young girls across Houston, Texas. When advances in DNA finally lead to his arrest, this psychopath eagerly confesses to multiple murders.

First responders arrive at a home in Ontario where a mother leads officers to the bodies of her two children. An investigation yields the truth: this awful tragedy isn't an accident but a carefully crafted killing by a vengeful psychopath.

A longtime nurse confesses to helping end the lives of numerous elderly patients at multiple nursing homes; detectives discover this is no angel of mercy; behind her unsuspecting persona lies a ruthless psychopath.

A failed actor take out his rage on the weakest members of society; after killing four people, a chance encounter with police leads to his downfall; the interrogation room becomes the stage for this killer's final performance.

Burlington Police get a call that a man killed his girlfriend. At the scene they find the man calm while his girlfriend's body lies nearby. He explains that he has other victims, revealing a history of psychopathic sexual deviancy.

A woman dies in a brutal stabbing at home. Police quickly locate the prime suspect: Antoine Bynum. In his interrogation, he appears to have a psychotic episode until detectives discover it's merely the ruse of a deranged psychopath.

A 17-year-old breaks into his family's cabin and steals a gun before beginning a horrifying road trip through Iowa. When officers catch up with him, a haunting portrait of a burgeoning psychopathic killer emerges.

Police respond to the site of a car crash alongside a highway in Grand Rapids, Michigan. Investigators at the scene quickly realize this is no accident, but rather an elaborate cover up for cold-blooded murder by relentless psychopath.

In rural Wilno, Ontario a vigilante leaves his home on a mission to confront three women who have rejected him over the years. His confession gives investigators picture of a cold-hearted psychopath with a long history of abusing women.

A woman reports her boyfriend is missing after finding a pool of blood in their apartment. When investigators start their search for answers, they are confronted with a sinister plot hatched by their roommate.