It didn’t take long for Bonin to succumb to his demons. His first known interaction with the law came in 1969 when he was accused of sexually abusing five boys in Los Angeles County. In each case, Bonin picked up the boys while driving around then handcuffed and sodomized them. Convicted of the assaults, Bonin was deemed a “mentally disordered sex offender” and rather than being sent to prison, was remanded to the Atascadaro State Hospital. He was examined by several neurologists, psychiatrists and psychologists, but what treatment he received for his damaged psyche is unknown.

Bonin had no memory of being physically abused. Doctors suspect he repressed the memory. "There is much data to indicate that Bonin was severely and recurrently sexually abused as a child," wrote one psychiatrist who examined William.

Doctors found a variety of other physical and psychological anomalies: brain damage in the area that is thought to restrain violent impulses; manic-depressive illness, and several unexplained scars on his head and backside.

Bonin, the doctors said, could not explain the scars.

Five years later, Bonin was released from the state hospital and placed on probation for five years. Clearly, by this point, William was unable to control his sick urges. He was a practicing pedophile, but hadn’t yet become a killer.

On the last day of summer vacation in 1975 David McVicker was thumbing for a ride to Huntington Beach. He was 14. Bonin offered McVicker a ride.

"He was totally cool--there was nothing in the least bit strange about him," McVicker told the Los Angeles Times shortly before Bonin’s execution.

Bonin asked the young man for sex and McVicker asked him to stop the car. William pulled out a gun, drove to a remote area and raped the boy.

Bonin began to choke McVicker with his own T-shirt--the same method Bonin would later use to kill several of his victims. McVicker, gagging, thought he was going to die.

When McVicker cried out, Bonin released him and to McVicker’s astonishment, “he apologized for choking me."

The attack on McVicker was especially notable for a couple of events: first, McVicker was the last successful attack for Bonin in which he did not kill, and it was the last time he would ever be known to admit regret for his actions.

Like other victims of sexual assault, McVicker’s suffering didn’t end when Bonin freed him. To this day, he told the Times, he suffers for Bonin’s crime.

Feeling dirty and ashamed, he told only his best friend what happened. His mother never wanted to hear the details, McVicker said. School no longer mattered and  he quit school that same year. He attended continuation high schools, but never received a diploma.

As Bonin's execution neared, McVicker said nightmares replaying the rape plagued him.

"Sometimes I wake myself up yelling," McVicker said. "Imagine going to sleep and getting raped 10 to 12 times a night."

McVicker did go to the police and based on his testimony, Bonin was convicted of lewd and lascivious conduct and sent back to prison. He served about three years behind bars.

Despite having been convicted of kidnapping and two counts of sodomy with a child in 1968, being diagnosed as a sexual predator and demonstrating criminal sexual conduct seven years later, Bonin was released by the California prison system in 1978.

Less than a year after being released from prison for the McVicker attack, Bonin found himself behind bars once again. He was picked up by Orange County officers while he assaulted a 17-year-old hitchhiker.

Incredibly, a records mix-up allowed Bonin to walk out of jail before his trial. Not surprisingly, he never showed for his day in court. That simple clerical error would eventually result in the deaths of more than three dozen young men.

Freed by a stroke of fate, Bonin had no intention of ever leaving witnesses to his crimes. A friend who would eventually collect a $20,000 reward for a tip that lead to Bonin’s capture remembers talking with William shortly before he disappeared into the seamy underworld of Los Angeles.

“I can remember he said, `No one's going to testify again. This is never going to happen to me again,'” his friend recalled in an interview 10 years after Bonin’s arrest.