Robert Durst, the onetime New York real estate scion convicted of one murder and suspected of others, died Monday at age 78.

Durst died in Stockton, California, where he was serving a life sentence. His lawyer, Chip Lewis, told The New York Times that Durst went into cardiac arrest at a hospital near the prison and could not be revived.

He’d contracted COVID-19 and was briefly placed on a ventilator last year, contributing to his preexisting health problems.

“Mr. Durst passed away early this morning while in the custody of California’s Department of Corrections,” Lewis said in a statement. “We understand that his death was due to natural causes associated with a litany of medical issues we had repeatedly reported to the court over the last couple of years.”

Durst, who has been incarcerated since his 2015 arrest, is estranged from his family, which operates some of the most prestigious real estate in New York City.

His trial was delayed due to the pandemic, but Durst was ultimately convicted in September of shooting his friend Susan Berman in the back of the head in 2000 ― out of fear, prosecutors alleged, that she would give up information about his connection to the death of his first wife, Kathleen McCormack. He was sentenced to life in prison in October.

McCormack vanished in February 1982 after allegedly telling a friend she was afraid of Durst. She is presumed dead, although her remains have never been found. A grand jury indicted Durst in her death in November, but he died before he could be tried.

In the wake of McCormack’s disappearance, Berman had served as a spokesperson for Durst, a college friend of hers. However, she later fell on hard times.

In 2015, Durst was dramatically arrested in New Orleans ― with a latex face-and-shoulders mask and over $40,000 in cash ― for Berman’s shooting, just hours before the final episode of a documentary about him, “The Jinx,” aired on HBO.

During filming of “The Jinx,” Durst seemed to inadvertently admit to the killings. While off-camera, but in the presence of a microphone he didn’t know was recording, he muttered “Killed them all, of course.” Jurors heard part of the 2015 recording at his trial.

He was held without bail, having attempted to flee a murder charge in Texas more than a decade prior.

In 2003, Durst was tried for the murder of a neighbor, Morris Black. He claimed that Black’s gun had gone off while Durst was trying to defend himself, and admitted to dismembering Black’s body out of concern, he said, that authorities would not believe him. He was ultimately acquitted.

Durst had been under growing scrutiny for McCormack’s disappearance, with a New York prosecutor reportedly seeking his indictment. In their victim impact statements, several of Berman’s friends and family members implored Durst to tell McCormack’s family what he allegedly did with her body.