Nick Reiner’s Former Roommate Claims Accused Killer ‘Hated His Parents, Especially’ Dad Rob Reiner

One month after he allegedly butchered his parents to death in their $13.5 million home in Brentwood, the National Enquirer has learned shocking new information about Nick Reiner.

Nick — who at press time had yet to enter a plea and was being held without bail at the Twin Towers Correctional Facility in downtown Los Angeles — reportedly suffers from schizoaffective disorder and changed his medication (due to unwanted weight gain) a month before the brutal double murders. “Once that happened, he went completely off the rails,” an insider close to the case tells the Enquirer.

Schizoaffective disorder is a chronic mental health condition with symptoms of both schizophrenia (psychosis) and a mood disorder, such as bipolar disorder or depression.

Antipsychotics and mood stabilizers may be used to treat the disorder. It is more difficult to treat if the patient has substance abuse issues.

At the time of the slayings, it’s unclear whether Nick — who has been to rehab at least 18 times and once referred to himself as a “nutcase” — was back on drugs.

Some sources believe Nick, 32, snapped because he’d relapsed and wasn’t on the correct medication, and he slaughtered his parents in a meth-fueled rage. (The murder weapon reportedly has not been found.)

“Nick is totally detached from reality,” says the insider. “He can’t seem to process or comprehend what he’s done.”

High-profile attorney Alan Jackson, who formally withdrew as counsel for Nick on Jan. 7, declared his former client “is not guilty of murder” under California law.

Danny Svilar, a Wyoming restaurateur who says he shared a room with Nick at a luxury $60,000-per-month Malibu rehab facility when they were both 15, told Daily Mail, “As soon as I saw that Rob Reiner and his wife, Michele, were murdered, I knew exactly who it was.”

“I would hate to see Nick try to plead this guilty or not guilty by insanity, when in reality he told me how much he f**king hated his parents, especially his father.”

And yet Rob, 78, and Michele, 70, tried to do everything to help their son, says Svilar. “Nick had no sense of gratitude, no sense of appreciation. He was just a f**king pompous little punk. He just wanted to be out, smoking pot, doing pills, doing whatever, and his family just wanted him to get help.”

Svilar recalls when Nick actually turned on him. “From the get-go, he was pretty welcoming, pretty funny,” he recalls. “But at the same time, there was this side of him that could just, like, flip.”

One time, “I compared him to looking like John Travolta’s son who died, and that set him off,” Svilar continues, referring to the actor’s late son, Jett Travolta. “We had good rapport at first, but then I was like, ‘Oh, my God, that’s who you remind me of.’ It kind of turned ugly after that. He definitely tried to get aggressive with me. He tried to get physical, and then a tech had to step in. He was getting into my face and raising a fist.”

Before their falling-out, Svilar, who was in rehab for a shopping addiction, says the two “would talk at night after lights were out, and some of the things that he would say really threw me the wrong way. Because I’m a 15-year-old boy in the same room as somebody with a crazy addiction. It was very, very chilling, but also, a crazy new experience for me.”

Little did he know years later Nick would allegedly slice his parents to death. “Rob and Michele were there for every single family group. They were there for every therapy session. They didn’t have to give me the time of day. I played frisbee with Rob. Rob Reiner, for God’s sake. They just wanted to get him well.”

“He really truly had no cause to hate them.”

Rob and Michele were reportedly awake and in separate rooms when Nick allegedly stabbed each of them to death.

“Whether he relapsed, or whether it was his mental disorder, I don’t know,” Svilar says, adding that he felt “chilled to the bone” by the murders and texted some of their old mutual friends from the Malibu facility in the aftermath of the tragedy.

“Everybody knew it was him,” he says. It’s a true Hollywood tragedy, adds Svilar, who wants people to know that Rob and Michele loved Nick and “did everything they could for him. They just wanted him to be well — and he did not want to be well.”

Nick’s arraignment on murder charges is scheduled for Feb. 23. A spokesperson for the Reiners says the family has “the utmost trust in the legal process.”