An aerial view of Hollywood Boulevard painted with the words "Black Lives Matter" as protests continue in the wake of George Floyd's death on Saturday in Los Angeles, California. Photo: AFP

An elderly ex-policeman confessed on Monday to being the violent serial prowler known as the "Golden State Killer," pleading guilty to 13 murders and admitting to dozens of rapes and break-ins that terrorized California during the 1970s and 1980s.

Joseph James DeAngelo, 74, entered the pleas as part of a broader deal with prosecutors sparing him from a potential death sentence in return for his admission to all of the offenses he stood accused of - charged and uncharged - in 11 California counties.

Under terms of the unusual plea agreement, approved by Superior Court Judge Michael Bowman at Monday's hearing, DeAngelo faces life in prison without the possibility of parole rather than a potential death sentence.

Prosecutors said the deal ensured that aging survivors and victims' relatives lived to see the case resolved, sparing them further legal proceedings likely to have dragged on for 10 years.

"The time for justice stands in front of us now," said Amy Holliday, deputy district attorney for Sacramento County.

The hearing was held in a Sacramento university ballroom, rather than a courthouse, to allow for socially distanced seating amid the coronavirus pandemic. The defendant and his attorneys wore medical-style, clear plastic face shields.

DeAngelo, dressed in orange jail garb, sat expressionless and slack-jawed in a wheelchair throughout the seven-hour proceeding.

He spoke in a weak, raspy voice only to give yes and no answers to procedural questions from the judge, 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 dozens of allegations of rape, robbery, and other crimes as prosecutors took turns presenting "factual-basis" statements graphically detailing every murder, sexual assault and burglary with which DeAngelo was accused. His admissions encompassed a total of 161 uncharged crimes, prosecutors said.

Prosecutors also revealed that on the day of his arrest, while alone in an interview room, DeAngelo was overheard having an animated conversation with himself, referring to an apparent alter ego named "Jerry," whom he described as being "in my head" and compelling him to "do those things."

One of many surviving victims who attended the hearing, Kris Pedretti, said she felt satisfied with the outcome of DeAngelo's plea, telling Reuters during a break, "I do think he is owning it."

Formal sentencing was set on August 17.