Conan O’Brien ‘stepped in and stopped guests at his party calling police’ after watching a fight unfold between Rob Reiner and his son Nick Reiner.

On Sunday, news broke that the legendary Hollywood director, 78, had been found dead with knife wounds at his Brentwood, Los Angeles home alongside wife Michele Singer, 68.

Soon after their son Nick, 32, was arrested in connection with their deaths, with police going on to charge him with two counts of first-degree murder. No alleged motive for the murders has been shared.

However just a few hours before allegedly murdering his parents, Nick apparently had an ‘explosive row’ with them at a Christmas party hosted by comedian and talk show host Conan, 62.

Earlier this week NBC News reported that Nick had been disruptive at the gathering, which left his parents ‘upset and embarrassed’. They also reportedly got into a ‘very loud argument’ with their son before leaving the party.

A few days on it’s now been claimed that Conan didn’t want guests at his party to call police after the argument.

‘They got in an argument, the father and son [at the party]. It got so bad and loud [that] someone wanted to call the police to report it,’ a source told the Daily Mail.

‘But Conan stepped in and said, “It’s my house, my party, I’m not calling the police”. He talked them out of calling the police.”

‘They got in an argument, the father and son. It got so bad and loud that someone wanted to call the police to report it.

A second source echoed those statements, noting that some guests suggested Nick needed to be placed on a psychiatric hold due to his behaviour.

‘When the s*** was hitting the fan, somebody said, “We need to call the police”. The conversation was about getting this kid put into a mental-health hold,’ they said.

‘It makes sense; who wants the cops showing up creating a scene? But the argument between Rob and Nick was pretty intense.’

During the party, Reiner had reportedly told some friends that he was ‘petrified’ that Nick could “hurt” him.

‘I can’t believe I’m going to say this, but I’m afraid of my son. I think my own son can hurt me,’ one of the guests claimed Reiner told him before leaving the party.

While one source said that ‘only the murderer is responsible’ for the deaths of Reiner and Singer – it must also ‘be gut-wrenching for Conan to learn that this is how things turned out’. ‘I’m sure that night is replaying for him over and over. It’s just so awful and sad,’ they said.

Earlier this week it was reported that Nick had not only argued with his parents but had a run-in with actor Bill Hader too.

Nick reportedly approached the Barry star while he was in the middle of a conversation with someone else before asking him: ‘What’s your name? What’s your last name? Are you famous?’

After Bill tried to cut off the chat by explaining he was speaking to someone privately, Nick stood still and stared at him before ‘storming off’.

‘Nick was freaking everyone out, acting crazy, kept asking people if they were famous,’ an insider told People. The publication also reported he unsettled guests by acting ‘creepily’.

Reiner and his wife had reportedly brought their son to Conan’s party to ‘keep an eye on him’.

After facing years of substance abuse Nick – who had been to rehab 17 times and faced periods of homelessness – had been living at his parents’ guesthouse for the past 18 months.

However, he’d recently been facing worsening schizophrenia and became ‘erratic and dangerous’ when doctors changed his medication just a few weeks ago, according to TMZ.

The couple’s bodies were discovered by their daughter Romy, 28, after they failed to answer their door.

Alongside her older brother Jake, 34, she’s since gone on to release a statement describing the ‘unimaginable pain’ of losing their parents.

‘Words cannot even begin to describe the unimaginable pain we are experiencing every moment of the day,’ they wrote.

‘The horrific and devastating loss of our parents, Rob and Michele Reiner, is something that no one should ever experience.

‘They weren’t just our parents; they were our best friends.’

The statement went on to say that Jake and Romy were ‘grateful’ for the outpouring of support since their parents were found dead.