Rob Reiner and Son Nick Had Loud Argument Night Before Murder.

Rob Reiner and his wife, Michele Singer Reiner, had a difficult interaction with their son Nick Reiner on the night preceding their murder.

A source revealed exclusively to Us Weekly that Rob, Michele, and their 32-year-old son Nick attended a Christmas gathering hosted by Conan O’Brien on Saturday, December 13. According to the insider, Nick allegedly behaved in a “creepy” manner during the celebration before leaving.

“Nick approached other guests at Conan O’Brien’s party to ask if they were famous,” the source elaborated.

TMZ reported that Rob and Nick were involved in a “very loud argument” during the party, which was audible to other attendees. Rob and Michele departed the event shortly after — only one day before they were discovered dead “from apparent stab wounds” in their Los Angeles residence. Us Weekly has contacted O’Brien’s representative for comment.

What Rob Reiner's Son Nick Said About Addiction, Their Complex Relationship

Nick was apprehended on Monday, December 15, and is currently being held without bail as authorities investigate Rob and Michele’s homicides. The couple, who married in 1989, had three children: Jake, Nick, and Romy. (Rob had also adopted Tracy, his ex-wife Penny Marshall‘s daughter.)

Before Rob and Michele's deaths at ages 78 and 68, respectively, they were open about the fact that Nick’s substance abuse struggles had created a division within the family. Nick first began to battle drug use during adolescence, resulting in his initial rehabilitation stay at age 15.

Following several relapses and treatment attempts, Nick eventually lived on the street.

“I experienced homelessness in Maine. I experienced homelessness in New Jersey. I experienced homelessness in Texas,” Nick told People magazine in 2016. “I spent nights sleeping rough. I spent weeks sleeping rough. It was unpleasant. If I insisted on doing things my way instead of participating in the programs they suggested, I had to be homeless.”

Nick attributed his recovery to this experience.

“Having to confront those issues shaped me into who I am now,” he added at the time. “I met amazing people there, people so unlike those in my typical circle. Now, I have been back home for a significant period and have acclimated to life in L.A. and being around my family again.”

Nick continued: “My life was at risk while I was out there. It was pure chance I survived. I went through many dark years.”

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After using these life experiences as inspiration for the 2015 film Being Charlie, Rob and Michele expressed remorse regarding how they handled the situation.

“When your child experiences difficulties, [as] the parent, your primary duty is to keep them safe. I would go to great lengths to ensure that,” Rob said during a Build Series interview at the time. “Ultimately, I understand my child better than any professional, and I probably should have relied on my personal intuition; that is one of the lessons I learned from the entire ordeal.”

Rob also disclosed that he apologized to Nick regarding their handling of his issues.

“We would not listen when Nick told us the method wasn't working for him,” Rob explained to the Los Angeles Times in 2016. “We were desperate, and because those individuals possessed professional credentials, we listened to them instead of listening to our son.”

Michele, meanwhile, added during the interview, “We were heavily swayed by these individuals. They told us he was a liar and attempting manipulation. And we believed them.”