Joseph James DeAngelo, a 74-year-old former California cop known as "the Golden State Killer," has now received multiple life-in-prison sentences.

DeAngelo previously pleaded guilty back in June to 13 murder charges, as well as 13 rape-related charges, as part of a plea deal. Per the Associated Press, moments before his sentencing on Friday, DeAngelo—whose long-unsolved case was the subject of this year’s HBO series I’ll Be Gone in the Dark—claimed to victims that he was "truly sorry" for his decade of brutal violence.

All told, DeAngelo is estimated to have amassed 87 victims across 53 crime scenes in 11 different counties in the state. Due to the scope of his pattern of brutality, prosecutors were forced to sentence DeAngelo in a university ballroom with a size large enough to hold attending survivors and their family members.

The Golden State Killer is also the subject of a true crime novel by the late Michelle McNamara, the creation and impact of which serves as the basis for the aforementioned HBO series. McNamara is also the one responsible for coming up with the name "Golden State Killer," having done so as part of an effort to bring greater attention to DeAngelo, who had previously been referred in the press by other nicknames including the East Bay Rapist and the Visalia Ransacker.

Speaking on Friday, Sacramento Superior Court Judge Michael Bowman highlighted the importance of ensuring a man like DeAngelo was kept away from the public.

"When a person commits monstrous acts they need to be locked away where they could never harm another innocent person," Bowman said.