The HBO documentary The Jinx: The Life and Deaths of Robert Durst took a chilling turn at the end, with the film’s subject, real estate heir Robert A. Durst, seemingly confessing to murder.

The six-part series outlined the deaths Durst has been widely considered to have committed over three decades. There’s been an air of mystery around two out of three them, as he was acquitted of shooting a neighbor in 2001 thanks to a high-powered defense team. He admitted to cutting up her body and throwing it in the river.

New York Times reports in the final moment of the documentary, Durst whispers to himself while in a bathroom, “What the hell did I do? Killed them all, of course.” The moment was caught because he still had his mic pack on.

He has denied killing his wife Kathleen Durst in 1982 and his friend Susan Berman in 2000 but he’s been linked to both murders. Durst was arrested on Saturday in a Marriott hotel in New Orleans, where he had checked in using a fake name.

USA Today reports his Saturday arrest was in connection with Berman’s death, but authorities will likely now prosecute him for his wife’s death as well.

Filmmaker Andrew Jarecki told Good Morning America on Monday his crew had not noticed the confession because it was part of hours of footage and they weren’t filming him at the time.

"It took a while to really understand the impact of it. It was so chilling to hear it,” he said.

The Los Angeles Police said in a statement following the airing of the documentary, "As a result of investigative leads and additional evidence that has come to light in the past year, investigators have identified Robert Durst as the person responsible for Ms. Berman's death.”