Why do some killers like Ed Kemper go beyond murder and mutilate corpses? "The answer is, the killing alone is not psychosexually sufficient," said a forensic psychology professor.

Ed Kemper, also known as the Co-Ed Killer, murdered and dismembered 10 people, including his own mother. Former FBI agent John Douglas takes us through his extensive interviews with Kemper, which became the backbone of modern criminal psychology.

But Harold Cartwright said he "never felt unsafe" in Kemper's presence.

"I was getting less detectable," said Ed Kemper.

"I came from my mother, and in a rage, I went right back in," said Kemper.

Ed Kemper, also known as the Co-Ed Killer, murdered and dismembered 10 people, including his own mother. Former FBI agent John Douglas takes us through his extensive interviews with Kemper, which became the backbone of modern criminal psychology.

 Dubbed “friendly” and “cooperative” by law enforcement, Kemper divulged every detail of his crimes to law enforcement.

At an early age, serial killer Ed Kemper displayed disturbing behavior. Experts discuss Kemper’s obsession with death and the morbid role-play games he played with his sisters.