DA Confirms Rob Reiner and Wife Michele Were Killed with a Knife

Nick Reiner allegedly killed his parents Rob Reiner and Michele Singer Reiner using a knife, authorities confirmed Tuesday.

Los Angeles District Attorney Nathan Hochman confirmed the murder weapon while providing an update on the Reiners’ murder case at a press conference on the afternoon of Tuesday, Dec. 16.

Hochman announced that Nick, 32, will be charged with two counts of first-degree murder with special circumstances of multiple murders. He also unveiled a special allegation that Reiner used a knife in the killings. If found guilty, he could face life in prison or possibly the death penalty, the district attorney said.

“These are some of the most serious charges that a DA’s office can bring against anyone,” Hochman told reporters.

Hochman refused to answer whether the murder weapon has been recovered.

Rob, 78, and Michelle, 70, were found dead by their daughter Romy in their Los Angeles home on Sunday, Dec. 14, sources told PEOPLE.

Several hours later, Nick was arrested near the University of Southern California campus in connection with their murders. Hochman said the charges against Nick were being filed later Wednesday and that he was currently going through “medical clearance” before making his first court appearance, where he is expected to enter a plea.

Two sources told PEOPLE Nick and his father got into a heated argument at a Christmas party hosted by Conan O’Brien on Saturday night.

“Nick was freaking everyone out, acting crazy, kept asking people if they were famous,” one of the sources said, while the other source described the argument between him and his father as a “big fight.”

Rob and his wife of 36 years left the party soon after the argument. The couple was discovered dead in their 10,000 square foot Los Angeles home the next day. It’s not clear whether they died on Saturday or Sunday.

Rob and Michele first met while he was directing When Harry Met Sally… and later married in 1989. The couple had three children: Jake, 34, Nick, 32, and Romy, 28.

Rob also had an adopted daughter Tracey, 61, with his first wife, the late actress Penny Marshall.

Nick’s arrest Sunday night in connection with his parents’ murder has drawn increased attention to his past issues with addiction and mental health.

Nick previously spoke out about his struggles with addiction and homelessness, which began in his teens, telling PEOPLE in 2016 he cycled in and out of rehab beginning around the age of 15. As Nick’s addiction escalated, he said he drifted farther from home and spent significant stretches of his life homeless in multiple states.

Nick and his father’s 2015 film together, Being Charlie, was partly inspired by his years battling addiction and homelessness.

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Rob was the director of a number of iconic films, including This Is Spinal Tap (1984), Stand By Me (1986), The Princess Bride (1987) and A Few Good Men (1992), among others.

The son of legendary comedian Carl Reiner, Rob broke into Hollywood on the legendary sitcom All in the Family.