Authorities suspect that Rob Reiner’s daughter may have urged the police to apprehend her brother, Nick, after she allegedly found her parents deceased at their Los Angeles residence, according to recent reports.

Sources informed the Daily Mail that 28-year-old Romy Reiner went to check on her filmmaker father and mother, Michele, following a call from their masseuse who noted that the couple had not responded to their doorbell around 2 p.m. on Sunday.

Upon arriving at their $13.5 million mansion in Brentwood, Romy reportedly discovered her 78-year-old father and 70-year-old mother dead, with their throats allegedly slit.

In shock, Romy is said to have informed the police that a family member should be considered a suspect due to their perceived dangerous nature.

Her brother, 32-year-old Nick, who has a known history of substance abuse and unstable mental health, was subsequently arrested later that Sunday night.

He was booked on a federal murder charge on Monday morning, LA Sheriff’s Office records show, and is now being held in jail without bail after police determined he was ‘responsible’ for his parents’ deaths.

Nick attended a holiday party with Reiner and Michele on Saturday night, and reportedly left A-list guests concerned after getting into a ‘very loud argument’ with his parents before they left.

‘Nick was freaking everyone out, acting crazy, kept asking people if they were famous,’ a source told PEOPLE about the bash, which was hosted by comedian Conan O’Brien.

The tragedy comes after Romy previously shared her closeness with her brother, describing Nick as her ‘best friend’ and revealing that she had supported him throughout his battle with drug addiction.

Romy Reiner with her father during a holiday in recent weeks. She frequently shared images showing her with her dad

The tragedy comes after Romy previously shared her closeness with her brother, describing Nick as her ‘best friend’

LAFD responded to a call just after 3.30pm Sunday, and first responders then called the LAPD to the scene, which is now investigating the deaths as homicides; Reiner and Singer pictured in March in LA

In 2015, the Reiner family sat around a dinner table for an interview with the LA Times to discuss Being Charlie, a film Nick co-wrote inspired by his experience with drugs and rehab.

‘This is my best friend and I was there for all of it,’ Romy said at the time. ‘It’s weird but good to see it on the screen.’

Romy, who followed in her famous dad’s footsteps and worked as an actress, regularly shared pictures revealing her closeness with her family.

Her Instagram is littered with videos and pictures with her father, with a post from December 1 documenting their recent family holiday.

Snaps show her smiling with both her parents in the sea, with a sweet caption professing she was ‘thankful for family’. 

But Reiner and Michele’s relationship with their youngest son, Nick, was seemingly more fraught than the one they shared with their daughter, who lived over the road from them.

In the months leading up to her death, Michele is said to have been anguished over her son’s spiraling mental illness and drug issues, telling friends ‘we’ve tried everything, ‘ according to TMZ. 

Reiner and his son Nick attend a screening of Being Charlie in New York, 2016

Renier and his wife met on the set of 1989’s When Harry Met Sally and wed that year. They had three children: (L-R) Jake, Romy and Nick; the family is pictured in 2014 in NYC

In the 2015 LA Times sit-down, Nick’s parents expressed regret at how they had dealt with their son’s addiction, saying they failed to listen to their son and instead relied on medical professionals to get him through it.

‘When Nick would tell us that it wasn’t working for him, we wouldn’t listen. We were desperate and because the people had diplomas on their wall, we listened to them when we should have been listening to our son,’ Reiner said of his son, who the family said had achieved sobriety at the time.

Michele added: ‘We were so influenced by these people. They would tell us he’s a liar, that he was trying to manipulate us. And we believed them.’

Referring to his drug addiction, Nick added: ‘I got sick of it. I got sick of doing that shit. I come from a nice family. I’m not supposed to be out there on the streets and in homeless shelters doing all these f*****-up things.’

Nick previously described how he first attended rehab around his 15th birthday, before going on to experience periods of homelessness. 

In 2016, when Nick was aged 22, he said he had gone to rehab 17 times, adding that he had been left homeless after refusing to get help on multiple occasions. 

‘If I wanted to do it my way and not go to the programs they were suggesting, then I had to be homeless,’ he told People, seemingly referring to his family.

‘I was homeless in Maine. I was homeless in New Jersey. I was homeless in Texas. I spent nights on the street. I spent weeks on the street. It was not fun.’ 

The $13.5 million six-bed home of Reiner and his wife Michele, in Brentwood, California

A satellite view of the mansion in Los Angeles, where the couple were slain on Sunday

The screenwriter co-wrote the semi-autobiographical movie Being Charlie about his struggles with drug addiction and the impact it can have on a family.

He worked on the film from rehab and collaborated with his director father on the project, which depicts the strained relationship between an actor father and his addict son. It tracks closely with the Reiner family’s own experience, they said at the time.

It ends with an apology from the father about the occasionally harsh way he treats his son, including enforced stints in rehab, something Reiner said he gave his son in real life.

In a 2016 interview with the BUILD series while promoting their film, Nick said that he ‘didn’t bond’ well with his father when he was younger, and that working on Being Charlie ‘made me feel closer to him.’

He said at the time of the film’s release that he hoped to stay off drugs so that he would never be homeless again: ‘When I was out there, I could’ve died. It’s all luck. You roll the dice and you hope you make it.’

In September this year, Reiner and Michele posed for their final full family photo with Nick, Romy and their eldest son Jake and his wife Maria Gilfillan at the premiere for Spinal Tap 2, which he directed and wrote. Jake was a news reporter in Houston, Texas, and now writes screenplays.

The Los Angeles Fire Department (LAFD) confirmed it was called to the couple’s Brentwood home at about 3.30pm on Sunday and found a man and woman dead in the property. 

A Reiner family spokesman confirmed the death of the director and his wife, saying: ‘It is with profound sorrow that we announce the tragic passing of Michele and Rob Reiner.

‘We are heartbroken by this sudden loss, and we ask for privacy during this unbelievably difficult time.’