Photo Credit: www.morguefile.com

Here is something you don’t see everyday on TV: An On-Air Confession.

Estranged real-estate heir Robert Durst made a shocking confession to his long-suspected involvement in the deaths of three people in the final episode of a six-part HBO documentary about him that aired on Sunday night.

Near the end of the show, Durst accidentally whispered into the microphone “What the hell did I do? Killed them all, of course.”

Durst was arrested on Saturday based on new evidence provided by the documentary. Susan Berman, one of Durst’s murder victims may have known about his wife’s disappearance.

The FBI reportedly believed that the 71-year-old, who has an estimated wealth of $100 million, was about to flee the U.S. possibly for Cuba.

Durst was suspected of involvement in mysterious 1982 disappearance of his first wife Kathleen McCormack in New York. She has never been found. Durst admitted murdering neighbor Morris Black in Texas in 2001, he was found not guilty in 2003 after claiming the killing was in self-defense. He dismembered body, putting it in bags and dumping in Galveston Bay. Durst had moved to Texas and was pretending to be a mute woman named Dorothy Ciner at the time of the killing.