Nick Reiner’s presence at Conan O’Brien’s Christmas party last weekend was not planned — and, according to a new report, it stemmed from growing concern within his family about his well-being. Multiple outlets report that Nick Reiner, 32, was not originally invited to the holiday gathering hosted by O’Brien. Instead, his parents, filmmaker Rob Reiner and Michele Singer Reiner, asked if their son could accompany them because they were reluctant to leave him home alone.

Parents reportedly feared leaving him unsupervised

According to The Hollywood Reporter, the Reiners had grown increasingly alarmed by Nick’s behavior in recent weeks. The outlet cited sources who described his conduct as “often extreme and stressful,” adding that it had escalated to a point the family found deeply concerning.

As a result, Nick Reiner had reportedly been staying in a guesthouse on the family’s Brentwood, California, property under what was described as “watchful supervision.”

The decision to bring him to the party, the report said, was driven by fear of leaving him alone.

Awkward encounters at the party

Once at the gathering, Nick Reiner allegedly made several guests uncomfortable by repeatedly asking three questions: their first name, last name, and whether they were famous.

One interaction reportedly escalated into an awkward exchange with comedian Bill Hader. According to the report, Nick eventually stormed off following the encounter.

Witnesses told the outlet that Rob Reiner confronted his son over what was described as “asocial and unsettling behavior” before apologizing to O’Brien and leaving the party early with his wife and son.

A tragic turn the following day

The events at the Christmas party took on far greater significance the next day, when Rob and Michele Reiner were found dead in their home.

Nick Reiner was subsequently arrested and charged with their murders. Authorities say he is being held without bail at Los Angeles’ Twin Towers Correctional Facility.

He did not appear at his arraignment Tuesday after officials said he had not yet been medically cleared. He has since been placed on suicide watch.

Hotel stay and arrest details

Before his arrest, investigators say Nick checked into the Santa Monica Pierside Hotel, where he allegedly left behind a bloodstained room.

Law enforcement later took him into custody. The investigation remains ongoing, and officials have not released further details about the timeline or motive.

Family and friends recall recent optimism

Friends and family members told Page Six that Nick Reiner appeared to appear stable in the weeks before the incident.

Barry Markowitz, a close family friend, said Nick had stayed with the Reiners last month and seemed to be doing well.

“He looked great,” Markowitz said, adding that he believed Nick was struggling with “a sickness” despite the strong bond within the family.

Rob Reiner echoed that sentiment in a September interview with NPR, saying his son was in a “really great place” and had been sober for six years after battling addiction.

A case still unfolding

The reported circumstances surrounding Nick Reiner’s attendance at the Christmas party now stand as part of a broader and deeply tragic narrative — one that highlights the warning signs family members say they were struggling to manage.

Authorities continue to investigate the case, and no further court dates have been announced.