By EMILY SHAPIRO, ABC News(SACRAMENTO, Calif.) — Joseph DeAngelo, the man suspected of being the notorious Golden State Killer, has agreed to plead guilty to 13 counts of first-degree murder in front of dozens of victims and victims’ relatives, prosecutors said.The death penalty will be taken off the table and he will serve life without parole, Sacramento County Deputy District Attorney Amy Holliday said at Monday’s hearing.After DeAngelo was taken into custody in 2018, he said to himself in an interview room, “I did all those things. I destroyed all those lives,” according to prosecutors.The plea deal will “allow the remaining victims and family members … to hear the defendant admit that he committed these acts,” Holliday said.Instead of a courtroom, DeAngelo, in an orange jumpsuit and using a cane, appeared in a California State University–Sacramento ballroom. With over 150 victims and relatives expected to attend, prosecutors sought a room that would be large enough to accommodate them and promote social distancing, The Sacramento Bee reported. The ballroom can hold 2,000 people.Victims and their family members nodded their heads as DeAngelo acknowledged the multiple counts against him in a weak, strained voice.DeAngelo, now 74 years old, was accused of committing 13 murders as well as multiple rapes and burglaries in the 1970s and 80s, terrorizing communities from Northern to Southern California.DeAngelo was a police officer during the crimes in the 1970s.DeAngelo on Monday admitted to shooting and killing Claude Snelling in front of Snelling’s daughter when he broke into their home in September 1975. DeAngelo kicked the daughter three times in the face and then fled, prosecutors said.DeAngelo admitted to the attempted murder of a police officer but he is not charged with the crime. DeAngelo shot at the officer when the officer confronted him trying to ransack a home in 1975.Among the survivors was Jane Carson-Sandler, who was home with her 3-year-old son when she was raped in 1976.”He told us, with clenched teeth, ‘Shut up or I’ll kill you,” she told ABC News in 2018.”After the rape was over, praise the Lord he moved my son back next to me. I could feel his body, and then I was relieved,” she said. “Then [the rapist] said, ‘Don’t move, or I’ll come back and kill you.'”DeAngelo on Monday admitted to the killing of a couple in Goleta, California, in 1979, after which he rummaged through the fridge and ate leftovers.Half a mile away, friends Cheri Domingo and Gregory Sanchez were killed at a Goleta home in July 1981.Sanchez was shot and then beaten to death, bludgeoned in the head two dozen times, prosecutors said.DeAngelo then bound Domingo, raped her and beat her in the head more than 10 times, prosecutors said.Domingo’s daughter, Debbi Domingo McMullan, told ABC News there’s “no such thing as closure. It’s a lifelong process.”The “Golden State Killer” crimes went unsolved until April 2018, when DeAngelo was arrested in Sacramento County. DeAngelo became the first public arrest obtained through genetic genealogy, a new technique that takes the DNA of an unknown suspect left behind at a crime scene and identifies him or her by tracing a family tree through his or her family members, who voluntarily submit their DNA to public genealogy databases.This allows police to create a much larger family tree than using law enforcement databases, such as the Combined DNA Index System, aka CODIS, in which an exact match is usually needed.To identify DeAngelo, investigators narrowed the family tree search based on age, location and other characteristics.Authorities surveilled DeAngelo and collected his DNA from a tissue left in a trash. Investigators plugged his discarded DNA back into the genealogy database and found a match, linking DeAngelo’s DNA to that gathered at multiple crime scenes, prosecutors said.Since DeAngelo’s arrest, over 150 suspects have been identified through genetic genealogy.Copyright © 2020, ABC Audio. All rights reserved.