Rob Reiner and his wife, Michele Singer Reiner, were reportedly keeping a close eye on their son, Nick Reiner, during a holiday gathering hosted by Conan O'Brien.

According to several reports, the family interaction took place just hours before the couple were later found dead at their Los Angeles home.

Sources say the family attended the gathering out of concern for Nick's behavior, which had become increasingly troubling.

The party took place on Saturday night, Dec. 13. Sources told Rolling Stone that Rob and Michele asked in advance if they could bring Nick because they wanted to "keep an eye on him."

While there, Nick, 32, allegedly showed "anti-social behavior," including staring at guests and acting erratically.

One source told People, "Nick was freaking everyone out, acting crazy, kept asking people if they were famous."

TMZ first reported that Rob Reiner, 78, and Nick got into a "very loud argument" during the party.

Multiple sources later confirmed the heated exchange, saying the father and son appeared deeply upset. Rob and Michele reportedly left the party shortly after the fight.

By Sunday afternoon, Dec. 14, tragedy struck when Rob Reiner and his 68-year-old wife, Michele Singer Reiner, were discovered dead inside their residence.

The Los Angeles Fire Department was called around 3:30 p.m. to provide medical aid, but first responders discovered both victims deceased. Investigators later determined the deaths were homicides.

Nick Reiner Arrested on Felony Murder Suspicion

Nick Reiner was arrested later that evening at 9:15 pm local time. Police said they believed Nick was responsible for the deaths.

He was booked on suspicion of felony murder and remains in custody without bail as the case is reviewed by the Los Angeles County District Attorney's office.

Nick's relationship with his parents had long been complicated. He previously spoke openly about his struggles with addiction and mental health issues, which began in his teenage years.

Nick entered rehab for the first time at age 15 and spent years moving in and out of treatment facilities, People reported. At times, he also experienced homelessness in multiple states.

Despite those struggles, Nick worked with his father creatively. He co-wrote the semi-autobiographical film "Being Charlie," which Rob Reiner directed.

The film focused on the strained bond between a troubled son and a famous father, mirroring parts of Nick's own life.

Nick's last public appearance with his parents was in September at the Los Angeles premiere of "Spinal Tap II: The End Continues," where he posed alongside Rob, Michele, and his siblings.