EXCLUSIVE: Read Rob Reiner's Chilling Final 'Death Premonition' Words — And Discover Why War Is 'About to Break Out' Over Slain Hollywood Legend's $200Million Estate

Slain Hollywood storyteller Rob Reiner had a chilling premonition that something ghastly might happen hours before his troubled son Nick Reiner allegedly slashed his and wife Michele Singer Reiner's throats in their Los Angeles mansion – and now a battle may be brewing over the couple's $200million fortune, RadarOnline.com can ​​reveal.

The famed This Is Spinal Tap director, 78, shared, "I'm petrified ... I think my own son can hurt me," giving heart-stopping insight into his terror-stricken state of mind, informants confide.

The remark was allegedly made at a holiday bash thrown by former late-night host Conan O'Brien on Dec. 13 – the day before Reiner and 68-year-old Michele's butchered bodies were discovered at their $13million home.

Sources said Nick, 32, acted so bizarrely at the festive event that O'Brien had to urge fellow guests not to call the cops, and the three Reiners left after the parents argued with their offspring.

Hours later, the beloved Stand by Me filmmaker and his wife of 36 years were found savaged from what officials called "multiple sharp force injuries," and Nick was slapped with two counts of first-degree murder.

Before backing out of the case, the accused killer's previous lawyer, Alan Jackson, urged against "a rush to judgment," but sources claimed after the slaughter, Nick left a Santa Monica hotel room stained with blood.

If found guilty of the double murder, Nick – the second-born of Rob and Michele's three kids, who also include actors Jake, 34, and Romy, 28 – could face up to life in prison or even the death penalty.

Jackson, who previously defended accused sex pests Kevin Spacey and Harvey Weinstein, reportedly charges as much as $2,000 an hour, and sources say the bill for his services is being footed by the Reiners' estate.

Sources said many in the forgiving family wish to see Nick – who was said to be diagnosed with schizophrenia – institutionalized rather than rotting behind bars, yet others are objecting to having a single penny of the Reiners' fortune used to defend the adored couple's alleged executioner.

Nick has a history of cocaine and heroin abuse, has been to rehab 18 times and once lived on the streets in New Jersey, Texas and Maine.

Sources alleged the Being Charlie screenwriter's doctors fiddled with his mental illness meds in the weeks before the slayings to improve his condition – but those changes rendered him "erratic and dangerous!"

An insider shared: "The reality is he had violent outbursts. The family has been scared of him."

Another source said: "This is not the first time [Nick] has been violent. I know of another incident a few years back."

According to reports, an unsettling homemade video, in which Nick threatens to kill a dog and pretends to snort powdered drugs, resurfaced.

David Manheim, who knew Nick, claimed the longtime addict felt crushing pressure to live up to the achievements of his famed father as well as his comedy legend granddad, Carl Reiner, creator of The Dick Van Dyke Show.

"I think he wanted to be great," said Manheim, host of the Dopey podcast.