Brian Cohee Jr. was a 19-year-old from Grand Junction, Colorado, who gained national attention in 2021 after being arrested for murder. In March of that year, police discovered that Cohee had killed 69-year-old Warren Barnes, a homeless man, before dismembering his body and storing parts of it in his bedroom. This documentary explores the case using body cam and interrogation footage.

In What Makes A Killer, we delve into the dark psychology of psychopathy - the personality disorder that drives some of the world's most notorious killers. Through the harrowing cases of Fred and Rose West, Ted Bundy, and Brian Cohee Jr., experts including psychologist Dr. Peter Hughes, psychiatrist Dr. Sohom Das, forensic specialist Dr. Jeane Gerard, criminologist Jane Carter Woodrow, and crime author Geoffrey Wansell unravel what lies behind the mask of charm, control, and cruelty.