Joseph James DeAngelo should have protected the community he lived in as one of California's police officers.
But the twisted ex-cop was responsible for some of the most gruesome murders America has ever seen during his 12 year killing spree.
DeAngelo became known as the Golden State Killer and has pleaded guilty to 13 murders in a plea bargain that will see him spared the death penalty.
But he is also suspected of being responsible for a further 51 rapes and 150 burglaries throughout California during the 1970s and 1980s.
The serial killer has been described as a "real life Hannibal Lectur" after he finally admitted his horrifying crimes.
Victims of ex-policeman Joseph James DeAngelo applauded as he was led out of court after pleading guilty to 13 murders, with some shouting: "Bye, bye! Go! Enjoy the dark."
Sacramento County District Attorney Anne Marie Schubert then described DeAngelo as "the real life version of Hannibal Lecter" and a "monster".
The 74-year-old pleaded guilty on Monday to 13 murders and confessed to dozens of rapes and home invasions that terrorized much of California during the 1970s and '80s.
He entered the pleas as part of a broader agreement with prosecutors sparing him from a potential death sentence in exchange for his admission to all offenses he stood accused of - charged and uncharged - in 11 California counties.
Under terms of the unusual plea deal, outlined by prosecutors and Superior Court Judge Michael Bowman at Monday's hearing, DeAngelo faces a sentence of life in prison without the possibility of parole.
Prosecutors said they wanted to ensure that the dwindling number of aging survivors, victims' families, witnesses and investigators would live to see resolution of the case, saving them from legal proceedings that might have dragged on for another decade.
"They deserve the opportunity, the victims and the next of kin, to be present when the verdicts are finally read," said Amy Holliday, deputy district attorney for Sacramento County.
"The time for justice stands in front of us now."
The plea hearing was held in a ballroom at Sacramento State University, rather than a courthouse, to allow for socially distanced seating amid the coronavirus pandemic.
The defendant and his attorneys all wore medical-style, clear plastic face shields.
DeAngelo, dressed in orange jail garb, sat expressionless in a wheelchair, his mouth agape, throughout much of the seven-hour proceeding.
He spoke in a weak, raspy voice only to give yes and no answers to procedural questions from the judge at the start of the hearing, and later to answer "guilty" when Bowman asked his plea to each of 13 counts of first-degree murder and kidnapping.
He also replied "I admit" to successive allegations of rape, robbery, weapon offenses and other crimes as prosecutors took turns presenting "factual-basis" statements graphically detailing every murder, sexual assault and home invasion with which DeAngelo was accused.
His admissions encompassed a total of 161 uncharged crimes, prosecutors said.
Police had been investigating the harrowing rapes and murders for 40 years when DeAngelo was finally arrested in 2018.
His crimes had spanned a huge area of California and for years officers didn't connect them all and believed they were the work of separate criminals.
The murders, rapes and burglaries led to nicknames the Visalia Ransacker, the Diamond Knot Killer, the Original Night Stalker and the East Area Rapist.
It was decades before detectives connected the harrowing crimes and realised they were all the work of one man.
DeAngelo was a former police officer who had also served in the Vietnam War and then worked as a car mechanic.
He was finally tracked down and arrested when his DNA was matched with a genealogy website.
It was painstaking work and investigators had to build a family tree dating back to the 1800s to find their suspect.
Police them trailled him and picked up a piece of rubbish he had put in a litter bin. They used this to match his DNA from several of the crime scenes.
When he was arrested, DeAngelo is said to have officers that he had been forced to commit the horrific rapes and murders because of an uncontrollable force inside him.
Sacramento County prosecutor Thien Ho told the court that when the killer was alone in a police interview room he said "I did all that".
He is then said to have added: "I didn't have the strength to push him out. He made me. He went with me. It was like in my head, I mean, he's a part of me.
"I didn't want to do those things. I pushed Jerry out and had a happy life. I did all those things. I destroyed all their lives. So now I've got to pay the price."
Since his arrest DeAngelo has been kept in isolation in a Sacramento jail.
He is expected to be sentenced to life in prison in August.
