Arrested millionaire says in HBO finale he 'killed them all'

The oldest son of the late real estate mogul Seymour Durst, whose Durst Corporation manages 1 World Trade Center, Robert Durst became estranged from his family when his brother Douglas was chosen to run the family business. Durst has always maintained his innocence in the 2000 murder of Susan Berman, whose father was an associate of Las Vegas mobsters Bugsy Siegel.

For years Robert Durst, estranged scion of a wealthy New York family, frustrated law enforcement officials in multiple states in connection with the deaths of his wife and a friend.

Robert-Durst-sits-in-court-during-a-pretrial-hearing-for-the-September-2001-murder-of-Morris-Black-in-Galveston-Texas-in-this-September-22-2003-file-photo-Reuters

Yet, in a move that has baffled legal experts, he agreed to participate in a TV series on his life. And in an unguarded moment during the shooting gave himself away.

"What the hell did I do," he whispered to himself, in the final episode of the show The Jinx: Life and Deaths of Robert Durst" on Sunday, "Killed them all, of course."

His wife went missing in 1982. His friend was found dead execution style - a bullet in the head in 2000. And a neighbor was found floating in parts in a Texas river in 2001. He was charged in the 2001 killing, but was acquitted.

FBI arrested Durst, 71, at a New Orleans hotel on Saturday where he was staying under a false name - he was apparently walking about in the lobby muttering to himself.

Durnst was once being groomed to take over the family business in realty - they own and run 11 major skyscrapers in New York City - but lost out to his younger brother.

Growing up, Durst, had seen his mother kill herself by jumping off a building, and was never able to get over it. His life story was turned into a film in 2010, with Ryan Gosling playing him.

The film, "All good things", apparently moved him so much that he agreed to speak to makers of that film for a documentary, ignoring, according to reports, his lawyers' advice.

"The Jinx.." started running on HBO, and expecting renewed interest in the case, Los Angeles police reopened probes into the murder of the friend, Susan Berman.

She was found dead on Christmas eve in 2000, and the same day local cops got an anonymous letter telling them they could find a "cadaver" in her house.

Addressed to Beverly Hills police, Beverly was misspelt as "Beverley". The writing, and the mistake, matched a letter Durst had written Berman, that the filmmakers had obtained.

The story is not over yet. Durst's lawyer told LA Times, "There has been rumor, innuendo and speculation for a number of years, and now we're going to get our day in court on this."