Killer made ‘most chilling end to documentary ever’ after forgetting his mic was still recording

An American real estate heir made the ‘most chilling end to documentary ever’ after forgetting his mic was still on.

Born into the wealthy Durst family of New York, Robert Durst was the eldest son of real-estate mogul Seymour Durst.

Despite having such luxuries, his adult life consisted of a series of disturbing events, such as the disappearance of his wife, Kathleen, in 1982.

Durst became a key suspect, given that the couple’s marriage had been troubled, although he was never formally charged at the time.

No body was ever found, and it remained a cold case until new evidence emerged.

Years later, Durst’s unofficial spokesperson and longtime friend, Susan Berman, was found shot in her Los Angeles home in 2000.

An anonymous letter was sent to police on the same day Berman was found murdered, containing details about the location of a body, which appeared to show knowledge of a murder scene.

Durst's wife went 'missing' in 1982 (NY Daily News via Getty Images)

The note was unusual because it included phrasing and knowledge that only someone close to the case could have known. Investigators later linked it to Durst, who said: "It’s very difficult to believe, to accept, that I wrote the letter and did not kill Susan Berman."

The wealthy businessman then fled to Galveston, Texas where his neighbour Morris Black was found dead a year later.

He admitted to cutting up the body but claimed the shooting was an act of self-defense. In a surprising outcome, a jury acquitted him of murder, though he later served time for evidence tampering and bail jumping.

Durst confessed to the murder during the documentary (HBO)

Durst’s case re-gained national attention with the 2015 HBO documentary The Jinx, which uncovered new evidence and captured Durst muttering, 'Killed them all, of course', while off camera but still mic’d. Watch below:

At the end of the documentary, Durst excuses himself to go to the bathroom, and mumbles quietly to himself, only to realise that the the mic was still on.

“There it is… I’m caught,” he said. “What a disaster.

“What the hell did I do? Killed them all, of course.”

Durst died in prison in 2022 (Mark Boster/Los Angeles Times)

In 2021, he was convicted of Berman’s murder and later indicted for Kathie’s death.

Kathleen Durst's relatives said in a statement at the time: "Not a single day goes by that we do not think about our beautiful, smart, and kind sister, Kathleen. Today, more than ever before, it is clear that she was murdered by Robert Durst in Westchester County, New York on January 31, 1982. The evidence is overwhelming.

"Although Durst has now been rightly convicted of killing Susan Berman, who helped him conceal the truth about Kathie's death, the McCormack family is still waiting for justice. Kathie is still waiting for justice."

Durst died in prison in 2022 while appealing his conviction, leaving several mysteries unresolved.