EXCLUSIVE: Rob Reiner's Disturbed Son Nick Could 'Plead Insanity' to Save Himself from Death Penalty... as He's Accused of Slaughtering His Parents

Nick Reiner could attempt to convince a judge he's insane to avoid getting the death penalty, RadarOnline.com can reveal.

The 32-year-old, who is accused of killing his father, director Rob Reiner, and his mother, Michele Singer, appeared for the first time in court on Wednesday, December 17, and waived his right to enter a plea.

According to Oleg Nekritin, a defense attorney at the Law Offices of Robert J. DeGroot, the accused killer and his legal team may have a plan in place.

"Nick's legal team may have to plead an insanity defense or argue for a 'lesser' offense, such as manslaughter, if DNA evidence, cell phone location evidence, and Nick’s own statements show that he caused their deaths," Nekritin told Radar. "News reports of a verbal fight with his parents prior to the murder and behavioral issues may support these defenses."

Hours before Rob and Michele were found dead inside their California mansion, the couple and Nick, a former drug addict, attended Conan O'Brien's Christmas party. While at the festive bash, Nick is said to have been "acting crazy."

Other sources alleged the A Few Good Men director and his son got into a "very loud argument," with some claiming the exchange stemmed from Nick's refusal to return to rehab.

However, while a family friend was unable to confirm or deny the alleged holiday party fight, he believed the situation was "misinterpreted" and being "overblown."

The insider close to the family was also said to "take offense" to claims the argument led to Rob and Michele leaving the party early, which he claimed was not very likely, as the filmmaker had "grown used to" Nick's behavior over the years.

"Nick Reiner had struggled for more than half of his life with drug addiction, but the person close to the family said they were accustomed to working through his problems together," the source told The NY Times.

Nick's sister, Romy, was said to have "fled in anguish" after discovering her father's lifeless body. Nick was arrested soon after and was charged with two counts of first-degree murder, with a special circumstance of multiple murders and use of a deadly weapon.

During his court appearance, Nick walked in in shackles and seemed to be wearing a suicide prevention vest or smock. After waiving his right to a speedy arraignment and not entering a plea, Nick only spoke when Judge Theresa McGonigle asked if he understood his rights.

"Yes, your honor," Nick was heard muttering. He will remain behind bars without bail until his next court appearance, scheduled for January.

Nick's dark past has been pushed into the spotlight following the heinous crime, especially his struggles with his mental health and substance abuse. He was also open about his struggles; in 2015, he co-wrote the screenplay for Being Charlie, a semi-autobiographical film directed by his famous father about addiction and recovery.

The Hollywood star's troubled son landed in rehab 18 times, as he struggled with addiction since his teens. His addiction even led him to live on the streets.

An insider claimed Nick felt like an outsider within his family.

"It felt like he was the black sheep of his very perfect Hollywood family, so from a very young age, he started using drugs," the source claimed to The Daily Mail.

"He had so many resources available to him. The idea that he couldn't get any money is crazy. The idea that he would be willing to be homeless instead of going home to his beautiful mansion was crazy to me."

Nick's siblings, Romy and Jake, revealed the "unimaginable pain we are experiencing every moment of the day," in a heartbreaking statement." The horrific and devastating loss of our parents, Rob and Michele Reiner, is something that no one should ever experience. They weren’t just our parents; they were our best friends..."