Rob Reiner and his wife, Michele, were discovered in their bed with fatal throat wounds, potentially while they were asleep, according to an investigation insider who shared details with the Daily Mail.

This chilling revelation may assist authorities in piecing together the events leading up to the couple’s tragic deaths, for which their 32-year-old son, Nick, has been arrested.

The couple met their untimely end sometime between Saturday night—when Nick was reportedly observed acting erratically and engaging in a loud argument with his parents at a Christmas gathering hosted by Conan O’Brien—and approximately 3:30 p.m. on Sunday. It was at this time that their daughter, Romy, allegedly discovered their bodies in the family’s Los Angeles residence and called 911.

“It’s possible the attack occurred shortly after everyone returned home, suggesting he entered their room and committed the act during the night,” the source speculated. “They were in bed when it happened.”

As of now, the Los Angeles Police Department has yet to officially confirm any specific details regarding the location within the house where the Reiners’ bodies were found.

But the claim that his parents were found dead in their bed could suggest a small mercy in the tragic incident: that they may have been killed in their sleep.

TMZ first reported that Reiner, 78, had a ‘very loud argument’ with his son at O’Brien’s holiday bash on Saturday night, after which the legendary movie director and his wife left.

One partygoer told People magazine that ‘Nick was freaking everyone out, acting crazy, kept asking people if they were famous’.

Rob Reiner, 78, and his wife Michele were allegedly found in their beds with their throats slit by police after their daughter Romy called 911, sources exclusively told the Daily Mail 

The couple’s troubled son Nick Reiner, 32, has been arrested for their murders which allegedly occurred after a turbulent night of fighting at Conan O’Brien’s Christmas party on Saturday night

The front of late-night host Conan O’Brien’s mansion, the scene where Nick was reportedly acting erratically and locked in an intense argument with Rob and Michele during the party 

Fears for the Reiners’ safety were only raised when a masseuse arrived at their $13.5million mansion in the Brentwood district of LA at 2pm the next day and got no answer at the door, the Daily Mail previously revealed.

Their 27-year-old daughter Romy, who lives across the street, then reportedly investigated and called emergency services when she discovered the horrific scene.

The LA Fire Department says first responders were called to the Reiner home around 3.30pm on Sunday and tried to render aid to the stabbed couple, to no avail.

Nick, one of the Reiners’ three children, had been living in the mansion’s guest house, a source close to him told the Daily Mail.

‘Nick had been living in their guesthouse, the same one he destroyed more than once, but it had been like a revolving door all his adult life,’ the source said.

‘He would do meth and not sleep for days and then have outbursts, breaking things, punching walls.

‘He was a ticking time bomb. His drug use was getting worse and his parents wanted him out,’ claimed the friend.

Nick had been living in his parents’ guesthouse for the past five years as he battled drug addiction, sources told the Daily Mail. Though he has spoken of living on the streets, he posted this image on social media in 2015 with the caveat: ‘This is a set’ 

Nick’s sister Romy, who lived across the street from their parents, was the one who went to check on the house after no one had heard from Rob or Michele 

Reiner and his wife Michele were found dead at their $13.5million six-bed Brentwood home (pictured)

The screenwriter’s son was arrested at 9.15pm on Sunday night, booking records show. Bail on the murder charges was initially set at $4million but was later revoked

Nick was arrested at 9.15pm on Sunday night, according to his booking record, after he had checked into a motel close to Santa Monica’s famous pier.

Police reportedly raided the hotel room and found a shower ‘full of blood’, blood all over the bed and the windows blacked out with the bedsheets.

Nick’s bail for the murder charges was initially set at $4million but later revoked.

He is currently in the Twin Towers Correctional Facility in downtown LA.

His first court hearing, according to his Sheriff’s Department booking record, is set for 8.30am local time on Tuesday at the Clara Shortridge Foltz Criminal Justice Center.

It is customary for a defendant to be arraigned at their first court appearance, where they are advised of the charges against them, they are given the opportunity to enter a plea, and bail can be discussed.