DNY59/iStockBy EMILY SHAPIRO, ABC News(SACRAMENTO, Calif.) — Joseph DeAngelo, the man now known as the “Golden State Killer,” was confronted in court Thursday by the family members of people he murdered decades ago.‘I was the only living witness’On Sept. 11, 1975, DeAngelo, who was a police officer at the time, shot and killed journalism professor Claude Snelling in front of his daughter, Elizabeth, at their Visalia, California, home.“My father caught him twice peering in my bedroom window when he came home from teaching night school, and tried to chase him down but wasn’t able to catch him,” Elizabeth Snelling said in court Thursday.In the early hours of Sept. 11, Elizabeth Snelling, who was 16 years old, said she was awakened by an intruder in a ski mask who pointed a gun at her head.Snelling said the intruder told her “he was taking me with him and if I made any noise he would kill me.”DeAngelo dragged her out of the house with a gun pointed at her head, she said, and her dad charged out of the house.“DeAngelo fired two shots hitting my dad,” she told the court. “He then turned the gun on me as I was down on the ground. My only thought was, ‘this is it.’”“He started kicking me in the head and face then ran off,” she said.Claude Snelling was 45 years old and in “the prime of his life,” his daughter said, calling him her “hero.”“We somehow managed to stay in the same house but with added security. I slept in my mom’s room for the next year,” Elizabeth Snelling said.“Knowing that my dad’s murderer was never caught … left us all feeling very vulnerable,” she continued. “Since I was the only living witness … there was a chance he could come after me. The police gave us extra security and patrolled our neighborhood … but I still lived in fear.”“DeAngelo was able to live a normal life with his family for all those years while my family and I could not be with my dad,” she said. “I am so thankful that he will at least spend the rest of his miserable life in prison.”DeAngelo, a 74-year-old father and grandfather, was arrested in 2018. In June he pleaded guilty to 13 counts of first-degree murder as part of a plea deal, which also required him to admit to multiple uncharged acts, including rapes.The death penalty was taken off the table in exchange for the guilty pleas.Three days of victim and family impact statements began Tuesday with powerful words from rape survivors and their relatives. On Thursday, family members of the 13 people DeAngelo killed have their day in court.On Friday, DeAngelo will be formally sentenced to life without parole.‘If I had my way he would be shivering, blindfolded, naked and exposed’In July 1981, Cheri Domingo and her boyfriend Gregory Sanchez were killed.Sanchez, 27, was shot and bludgeoned in the head two dozen times, prosecutors said. DeAngelo then bound 35-year-old Domingo, raped her and beat her in the head more than 10 times, prosecutors said.“My heart is racing,” said Domingo’s daughter, Debbi McMullen, as she began speaking in court Thursday.McMullen, who was 15 at the time of her mother’s murder, said in her 20s “I started to sink into a depression that was undiagnosed and untreated for many years.”She said she “stumbled into drug use,” during which “a decade was lost.”“Mom would have helped,” she said. “She would have supported me and guided me toward solutions. She would have prodded me into admitting that I needed help.”By her mid-30s, McMullen was clean, sober and welcoming her children back home, she said. McMullen then learned her mother’s slaying may be the work of a serial killer and she poured her energy into helping solve the case.“I am not that lost teenager anymore. Today I am in the room with the pathetic excuse of a man who will now finally be held accountable,” she said. “If I had my way he would be shivering, blindfolded, naked and exposed every moment from now on.”‘He had no idea how much Katie and Brian were loved’In Feb. 1978, Brian and Katie Maggiore were shot dead while walking their dog. After Brian Maggiore was shot, his wife ran away and yelled for help, but DeAngelo caught up with her and shot her in the head, prosecutors said.Katie turned 20 years old four days before she was killed in “cold blood,” her brother said in court Thursday.“He had no idea how much Katie and Brian were loved. They have remained alive in all our hearts,” he said.‘Her future was stolen’Debra Manning and her boyfriend, Robert Offerman, were killed on Dec. 30, 1979.Manning was bound, raped and shot twice in the head, while Offerman was bludgeoned and shot four times, her friends said in a statement.“Her future was stolen,” they said.DeAngelo, who was a police officer from 1973 to 1979, committed 13 murders as well as multiple rapes and burglaries in the 1970s and 80s.The crimes, which terrorized towns from Northern to Southern California, went unsolved until April 2018, when DeAngelo was arrested in Sacramento County.DeAngelo was 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.To identify DeAngelo, investigators narrowed the family tree search based on age, location and other characteristics. Authorities conducted surveillance on 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 the DNA found at multiple crime scenes, prosecutors said.Since DeAngelo’s arrest, over 150 other crime suspects have been identified through genetic genealogy. Copyright © 2020, ABC Audio. All rights reserved.