From age 15 to 21, serial killer Ed Kemper was committed to Atascadero State Hospital in Northern California for killing his grandparents. While incarcerated at the all-male, maximum security facility, Kemper developed violent, sexual fantasies that he would soon act out on co-eds, his mother and his mother's friend.

"Here's a kid that had never had a girlfriend, and he describes that he would masturbate several times a day,” Harold Cartwright, a former investigator, told "Kemper on Kemper: Inside the Mind of a Serial Killer." "A lot of what he was thinking about during these activities was what he would do to his mother and perhaps to other women."

In various interviews, Kemper described his mother, Clarnell Strandberg, as an abusive alcoholic who fueled his murderous rage and became the main motivation behind his killings. 

Forensic psychology professor Louis Schlesinger explained, "He hated his mother, and it's sexually arousing and stimulating. What that tells me is, as an early adolescent, when people are just reaching puberty and their sexuality begins to take place, you already see the early signs of a fusion of sex and aggression."

After his release from Atascadero, Kemper abducted, murdered and dismembered six female students before having sex with their remains. In a gruesome final act, Kemper bludgeoned his mother with a claw hammer and strangled her friend, Sara “Sally” Hallett. When his mother was dead, he cut off her head and “humiliated” her corpse. He then placed her head on a shelf, “screamed at it for an hour” and threw darts at it. Later, Kemper removed Strandberg's tongue and larynx and put them in the garbage disposal.

"[W]hat people can't really understand easily is, why do they have to go beyond the murder? And the answer is, the killing alone is not psychosexually sufficient," said Schlesinger.

To hear more about Kemper's murders, watch "Kemper on Kemper: Inside the Mind of a Serial Killer" on Oxygen.

[Photo: Getty Images]