It is common for serial killers to claim some form of abuse as children and to use that history to try to avoid punishment for their crimes.
Childhood abuse has an established correlation to sexual deviancy later in life, experts said.
"Children who have suffered grow up feeling a profound sense of helplessness," Levin said. "Most compensate in a socially accepted way. But a few can't do that for some reason. Instead, they only feel powerful to the extent that they torture, rape, dismember and kill."
Dr. Michael Welner, a forensic psychiatrist, said that when those early traumatic experiences come during the victim's sexual maturation, "that rage can get blended in with their sexuality."
"Sadistic fantasies become increasingly dominant," he said.
But, Welner and other serial killer experts pointed out, many people have suffered abuse without going on to become killers.
"Not all serial killers are abused. There may be a correlation. It may contribute. But it's not the whole story. It's not even half the story," said James Fox, a criminologist who has researched serial killers.
Fox also warned that serial killers will lie to avoid punishment.
"Serial killers are typically accomplished liars and manipulators," he said. "You have to take what these people say not just with a grain of salt, but with the whole salt shaker."
ABC News Consultant Dr. Michael Welner is chairman of The Forensic Panel, a national forensic science practice. He is developing an evidence-based test called the Depravity Scale, http://depravityscale.org, which invites Americans to participate in surveys that are used to form a legal standard of what represents worst crimes.