LOS ANGELES — Rob Reiner’s son Nick was arrested on suspicion of murdering his parents after the Hollywood legend and his wife, Michele Singer Reiner, were found dead at their Brentwood home Sunday.

Los Angeles police Chief Jim McDonnell said that officers responded to the Reiner home at about 3:40 p.m. Sunday. Detectives from the elite Robbery-Homicide Division “worked throughout the night” and took Nick Reiner, 32, into custody.

“Our hearts go out to the family and friends of the Reiners,” McDonnell said during a news conference Monday. “A tragic incident.”

Authorities have issued a search warrant for the Reiner home, McDonnell said, calling it a “critical piece of our investigation.” The director was 78 and his wife was 70.

Family friends told the Los Angeles Times that Rob and Nick Reiner got into an argument Saturday evening at a party at Conan O’Brien’s home and that many people noticed Nick acting strangely at the party.

Nick Reiner, who had struggled with addiction for years, was living in a guesthouse on his parents’ property, family friends told the Times, and his mother had become increasingly concerned about his mental health in recent weeks.

The family friends, who did not want to be identified because of the nature of the crime, said that the Reiners’ daughter found her parents Sunday afternoon.

Law enforcement sources told the Times that there was no sign of forced entry into the home in the 200 block of Chadbourne Avenue. The source also said the Reiners had injuries consistent with being stabbed.

Nick Reiner was taken into custody at 9:15 p.m. Sunday and booked at 5:04 a.m. Monday, jail records show. He is being held on $4 million bail.

In interviews, Nick Reiner has described cycling in and out of rehab centers and experiencing bouts of homelessness as a teenager.

By 2015, he had gotten clean, working with his father on “Being Charlie,” a semi-autobiographical film about addiction and recovery. Rob Reiner directed and Nick co-wrote the film about a successful actor with political ambitions and a son addicted to drugs.

At the time of the premiere, the Times reported that Rob Reiner and his wife at their worst moments “wondered if there was an end in sight, and whether it would be the tragic one that a voice in the back of their heads kept telling them was coming.”

Rob Reiner has said the filming brought up tough memories.

“It was very, very hard going through it the first time, with these painful and difficult highs and lows,” he said. “And then making the movie dredged it all up again.”

But he said the process of making the movie was therapeutic, allowing them to work through a lot of past trauma and develop a closer relationship.

By Sunday evening, law enforcement had swarmed Reiner’s sprawling estate in Brentwood, though an eerie quiet hung over Chadbourne Avenue, which had been sealed from the public with yellow crime scene tape.

Police cars were stationed at either end of the block while a chopper circled overhead.

Officers spoke to a young man inside the sealed-off area who left the scene around 7:30 p.m. in a white Tesla and declined to speak to the media.

Council member Traci Park, whose Westside district includes Brentwood, said in a statement that the LAPD had increased patrols in the neighborhood “out of an abundance of caution.”

“As we continue to wait for more updates, I want to express my profound concern and sadness at the news coming out of Brentwood,” Park wrote in the statement. “We are in close contact with LAPD as the homicide unit continues their investigation.”

Mayor Karen Bass said in a statement that she was “heartbroken by the tragic loss of Rob and his wife Michele.”

“Rob Reiner’s contributions reverberate throughout American culture and society, and he has improved countless lives through his creative work and advocacy fighting for social and economic justice,” Bass said. “An acclaimed actor, director, producer, writer, and engaged political activist, he always used his gifts in service of others.”