Truth about what drove Rob Reiner's son to SNAP... as motive and grisly details of his campaign of terror emerge: 'Ticking time bomb'

Nick Reiner was a 'ticking time bomb' whose drug use spiraled out of control after his parents threatened to kick him out of their home, the Daily Mail can exclusively reveal.

The troubled 32-year-old, who was arrested Sunday night following the brutal stabbing deaths of his filmmaker father Rob Reiner, 78, and mother, Michele, 70, had been living in his parents' guesthouse in Los Angeles for the past five years - where his behavior had become increasingly erratic and frightening, insiders claimed.

'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,' a source close to Reiner told the Daily Mail on Monday. 

'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.

According to the source, Nick, who was one of three children, frequently laughed off the destruction he caused during drug-fueled episodes.

'He used to brag how he could get away with anything and took money from his parents for drugs and prostitutes.

'He would talk about this stuff in meetings, but then stopped going because he said it was too cultish,' the source claimed. 'He laughed about destroying his parents' guesthouse more than once. He was so nonchalant about it. 

Nick Reiner, who had lived on the streets growing up, posted this picture on his social media in 2015, but claiming in the caption 'this is a set'

Nick Reiner, who had lived on the streets growing up, posted this picture on his social media in 2015, but claiming in the caption 'this is a set'

Nick is pictured smoking a cigarette with his sister

Nick is pictured smoking a cigarette with his sister

'He kept saying he hadn't touched heroin, and that he could handle his weed, but that turned into meth and staying up for days and not eating,' the source claimed.

'He really had no control. He busted his hand when he punched the bathroom wall and refused to get help.

'He would fight with his parents because they would give him the ultimatum, take medication and stop using, or move out.

'When he started threatening his sister for confronting him that's when all hell broke loose,' the source claimed. 'His parents threatened to call authorities multiple times, but in the end didn't.'

Nick himself previously described one such explosive episode in chilling detail during a 2018 appearance on the Dopey podcast, a show focused on addiction and recovery.

During the August 18, 2018, episode, host David Mannheim asked him directly: 'What about when you wrecked the guesthouse on meth?'

'I got totally spun out on uppers,' Nick replied. 'I think it was coke and something else. I was up for days on end.'

Nick had been living at his parents guesthouse for the past five years as he battled drug addiction, sources tell the Daily Mail

Nick had been living at his parents guesthouse for the past five years as he battled drug addiction, sources tell the Daily Mail

A picture Romy shared on Instagram posing with her brother Nick

A picture Romy shared on Instagram posing with her brother Nick

He went on to describe destroying nearly everything inside the structure while in a drug-fueled frenzy.

'I started punching out different things in my guest house. I started with the TV and then went over to the lamp. Everything in the guesthouse got wrecked,' he said.

When Mannheim asked whether the violence was a way to release pent-up tension, Nick dismissed the idea.

'No, you're crazy. No logic,' he replied.

Mannheim, himself a longtime recovering addict, expressed concern during the interview and urged Nick to give sobriety another chance.

The resurfaced podcast has taken on grim significance in light of Sunday's killings.

Police arrested Nick at around 9.15pm on Sunday on suspicion of a felony after his sister Romy reportedly discovered her parents' bodies inside their Brentwood home. Both had suffered multiple stab wounds.

Sources previously told the Daily Mail that a masseuse came to the Reiners' home Sunday afternoon for an appointment and left when her ringing the doorbell and knocking went unanswered. This prompted Romy, who lives across the street, to visit her parents' home.

A satellite view of the $13.5 million LA mansion, where the couple were slain on Sunday

A satellite view of the $13.5 million LA mansion, where the couple were slain on Sunday

A security guard stands outside Reiner's mansion in the Brentwood neighborhood of Los Angeles on Monday, after the director and his wife Michele were found dead

A security guard stands outside Reiner's mansion in the Brentwood neighborhood of Los Angeles on Monday, after the director and his wife Michele were found dead 

Nick drew heavily on his history of addiction to write the semi-autobiographical movie Being Charlie, released in 2016 and directed by his famous father.

He co-wrote the film with Matt Elisofon, 34, whom he met in rehab. The two had a 'wonderful relationship', a source close to Elisofon told the Daily Mail.

But in recent years, the friendship disintegrated, as Nick continued to go in and out of rehab, while Matt has remained sober for 13 years, the source said.

'He went on vacation with the Reiners, he lived with them for months.

'Now he feels bad that he could have maybe done more. But I told him, you haven't spoken to Nick in five years. For the time that you were with him, you were a good friend to him.

'To think that however [Rob and Michele] were as parents, whatever they did right or wrong, at the end of the day they're going to die by their son? I just can't wrap my mind around it,' said the source, commenting on the as-yet-unproven allegation that Nick killed his parents.

'This is really, literally right through the heart.'

Elisofon did not respond to a request for comment.

Nick spoke publicly about beginning his first rehab stint around his 15th birthday, followed by 17 more visits over the next four years.

During that time, he later told People Magazine in 2016, he also experienced intermittent periods of homelessness.

'I was homeless in Maine. I was homeless in New Jersey. I was homeless in Texas,' he said. 'I spent nights on the street. I spent weeks on the street. It was not fun.'

Photos from the Portland, Maine, men's substance abuse rehab Foundation House show he was attending rehab over the course of two months in the fall of 2017.

Nick was pictured with other young men competing in a softball championship at Hadlock Field in Portland in September 2017 and hiking with a group in Baxter State Park the following month, on excursions run by the rehab facility.

Nick had previously spoken about his struggles with drug addiction

Nick had previously spoken about his struggles with drug addiction

Reiner and Michele (left) are pictured (L-R) with Romy, Nick, daughter-in-law Maria Gilfillan and Jake Reiner in September, their last public appearance as a family

Reiner and Michele (left) are pictured (L-R) with Romy, Nick, daughter-in-law Maria Gilfillan and Jake Reiner in September, their last public appearance as a family

Friends and family insiders say the warning signs had been present for years. 

Earlier on Monday, the Daily Mail revealed that Nick was known within the family's circle as an 'intense kid' who struggled with emotional regulation from an early age - prompting his parents to seek professional help long before his substance abuse took hold.

Celebrity yoga teacher Alanna Zabel, who worked with the Reiner family for nearly a decade, said Nick's behavior as a child was so extreme it inspired her to write a children's book about a boy with severe emotional outbursts.

'Nicky would barge in like the world was on fire, screaming, into our yoga sessions,' Zabel recalled. 'It was disruptive.

'He was really screaming, I have never seen a child like it.' 

Zabel said she even held private classes with Nick for a year in a bid to 'regulate him and calm him down.'

'His emotions were not being met on some level. He really needed attention, and needed it immediately when he needed it.

'He was just an intense kid.'

Zabel said the Reiners had hired a family therapist to help tackle the problems they faced with Nick.

'The fact that they were seeing a family therapist shows how much they cared. They were trying to figure it out,' said Zabel, who has a degree in child development.

Zabel described the Reiner parents as 'passionate,' 'hands-on parents' and 'loving.'

'I love Rob and Michele, so much. They were just so passionate. Both of them were very intensely passionate about their family, life, justice and creativity,' she said.

'Michele was a New Yorker living in California. She was really mindful, trying to raise her kids out of the pressures of Los Angeles and Hollywood. It was challenging and full-time.'

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