LOS ANGELES (CNS) - The son of writer/director Rob Reiner was charged Tuesday with two counts of first-degree murder for allegedly killing his parents inside their Brentwood home.

The murder charges against Nick Reiner, 32, include a special circumstance allegation of multiple murders, which could open him to a possible death sentence, if prosecutors opt to pursue capital punishment. That decision will be made later in the case, District Attorney Nathan Hochman said during a Tuesday afternoon news conference.

Reiner is also facing a sentence-enhancing allegation of the personal use of a deadly weapon -- a knife -- during the crime.

He is tentatively scheduled to appear in court Wednesday in downtown Los Angeles for arraignment. His defense attorney, Alan Jackson, told reporters Tuesday he had not been medically cleared yet to appear in court.

Rob Reiner, 78, and his wife Michele Singer Reiner, 70, were found dead around 3:30 p.m. Sunday in their home in the 200 block of Chadbourne Avenue, between Sunset and San Vicente Boulevards. Rob Reiner is best known for his iconic role on the classic sitcom "All in the Family," but also as a director of films such as "Stand By Me," "The Princess Bride," "A Few Good Men" and "When Harry Met Sally."

Nick Reiner was arrested around 9:15 p.m. Sunday in the Exposition Park area near USC and he was booked into jail early Monday morning.

Law-enforcement sources told TMZ that Nick Reiner was being held in administrative segregation at Twin Towers Correctional Facility in downtown Los Angeles and is on suicide watch.

Los Angeles Police Department Chief Jim McDonnell on Tuesday declined to provide any details on what led to Nick Reiner being identified as the suspect in the case. No information was provided on a possible motive for the killing.

Hochman confirmed that a knife was used in the killings. TMZ reported earlier that Reiner and his wife suffered "lacerations consistent with a knife," describing the victims as having their throats slit.

"Prosecuting these cases involving family members are some of the most challenging and most heart-wrenching cases that this office faces, because of the intimate and often brutal nature of the crimes involved," Hochman said. "Rob Reiner was a brilliant actor and director, an iconic force in our entertainment industry for decades. His wife, Michele Singer Reiner, was an equally iconic photographer and producer. Their loss is beyond tragic, and we will commit ourselves to bringing their murderer to justice."

According to multiple reports, the slain couple's 28-year-old daughter, Romy Reiner, discovered the bodies. One report suggested that a masseuse had shown up at the couple's home for a pre-scheduled appointment on Sunday but got no answer at the door and contacted Romy.

Sources told multiple outlets that Rob and Michele Reiner, along with Nick, attended talk-show host Conan O'Brien's Christmas party on Saturday night, and Rob got into a heated argument with Nick and wound up leaving the event with his wife. It was unclear when Nick Reiner left. TMZ reported that Nick Reiner spent Saturday night at a hotel in Santa Monica, and blood was later found in the room.

Nick Reiner has a documented history of drug addiction. In 2015, he worked with his father to write and produce a semi-autobiographical movie titled "Being Charlie," based on Nick's drug-addiction issues and the family's struggles to cope. Nick Reiner was publicly open about his addiction struggles, discussing the issue in multiple interviews with media outlets and on podcasts.

Nick Reiner described being in and out of rehab programs throughout his teen years, and spending time homeless in various states, including Texas, New Jersey and Maine. He also described an instance when he was high on cocaine for multiple days and trashed his parents' guest house.

According to TMZ, Michele Reiner had allegedly lamented to friends in recent weeks about Nick's mental health and addiction issues, saying, "We've tried everything."

A statement issued by the Reiner family was published by Variety on Sunday, 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."

The son of celebrated writer/producer/comedian Carl Reiner, Rob Reiner began his career in 1968, writing for "The Smothers Brothers Comedy Hour," on a writing team that included a young Steve Martin. Reiner also had bit roles in various TV shows, including "The Beverly Hillbillies" and "Batman."

His big break came with his casting as Archie Bunker's liberal son-in- law Michael "Meathead" Stivic on the groundbreaking sitcom "All in the Family" in the 1970s. The role won him two Primetime Emmy Awards.

But it was his work behind the camera that saw him achieve even more success. "A Few Good Men," starring Tom Cruise and Jack Nicholson, was nominated for an Oscar for best picture. His other credits included "This Is Spinal Tap," "Ghosts of Mississippi," "The American President" and "Misery."

Reiner's final film, "Spinal Tap II: The End Continues" was released in theatres Sept. 12.

Reiner was married for 10 years to actress/director Penny Marshall, but they divorced in 1981.

He met photographer Michele Singer while he was directing "When Harry Met Sally." Reiner often told the story about how his romance with Singer led him to change the ending to the movie -- with the characters played by Billy Crystal and Meg Ryan reuniting rather than going their separate ways.

Reiner and Singer married in 1989 and they had three children -- sons Nick and Jake and daughter Romy.

He was a vocal Democrat activist, helping to spearhead efforts to legalize same-sex marriage in California and to pass a 1998 initiative that created the First 5 California childhood-development services program, funded by a tobacco tax.

On Monday, a shrine of candles and flowers was growing at Reiner's Hollywood Walk of Fame star as fans expressed their grief. One of the flower arrangements placed on the star was accompanied by a handwritten note that read, "RIP Meathead."

Bill Handel