March 16: Since his first wife vanished more than three decades ago, Robert A. Durst, the eccentric and estranged son of one of New York's most prominent real estate dynasties, has lived under the suspicious gaze of law enforcement officials in three states.

They have followed his path from New York City to Los Angeles, where one of his closest friends was found dead in her home in 2000. They have tracked him to Galveston, Texas, where he fled after investigators re-opened the case of his wife's disappearance, and where he posed as a mute woman and shot and dismembered a neighbour in 2001.

Durst was acquitted in the Texas killing, and was never arrested in the disappearance of his wife or the death of his friend. But on Saturday, he found himself in custody once again, arrested on a charge of murder as he walked into a New Orleans hotel he had checked into under a false name.

Last night, in the final moments of the final episode of a six-part HBO documentary about him, The Jinx: The Life and Deaths of Robert Durst, Durst seemed to veer towards a confession that could lift the shroud of mystery that surrounds the deaths of 3 persons over the course of 3 decades.

"What the hell did I do?" Durst whispers to himself in an unguarded moment caught on a microphone he wore during filming. "Killed them all, of course."

Near the documentary's end, the filmmakers were packing up their equipment when Durst asked to use the bathroom. He did not remove his wireless microphone as he closed the door, however, and began to whisper to himself.

More than two years passed after the interview before the filmmakers found the audio. Durst's private monologue makes for good television. But it is unclear whether the recording of his comments could be used in court, some legal experts said, since they were made in a bathroom when he was alone and had an expectation of privacy.

"That's pretty damning stuff," said Daniel J. Castleman, the former chief of investigations in the Manhattan district attorney's office. "The question is: Is it admissible in court?" But Daniel C. Richman, a former federal prosecutor who is a professor at Columbia University Law School, said the statements could be admitted in court "so long as it can be shown that the tape wasn't tampered with."

In the years since his wife, Kathleen Durst, disappeared in 1982 after spending the weekend at the couple's country home in Westchester County, Durst has bounced in and out of jail for other crimes, cut ties with his family, remarried, and sued his brother for a $65 million share of the family fortune.

Through it all, he has maintained his innocence in the disappearance of his wife, while also denying any role in the 2000 death of the Los Angeles friend, Susan Berman.

His arrest on Saturday in a Marriott on Canal Street in New Orleans was in connection with Berman's death, though the Westchester authorities said they were still investigating him in his wife's case.

Durst was walking towards an elevator and mumbling to himself when FBI agents intercepted him at the hotel, a law enforcement official briefed on the investigation said.

He had checked in under the name Everett Ward, not the first time he had used an alias.

Durst is believed to have left Houston in a Toyota Camry on March 10, headed for New Orleans. Investigators involved in the case said they feared that the renewed attention brought by The Jinx would lead him to try to flee the country. Durst will plead not guilty, said one of his lawyers, Dick DeGuerin, who helped win Durst's acquittal in Galveston in 2003 and who said he expected to head Durst's defence team in Los Angeles.

"The rumours that have been flying for years will now get tested in court," DeGuerin said. As he watched the documentary last night with the filmmakers, James McCormack, the brother of Kathleen Durst, said, "Closure is near at hand; I feel in my heart."

It was Durst himself who may have set the latest twist in his bizarre saga in motion. Los Angeles prosecutors reopened their investigation into Berman's execution-style murder only after Durst agreed to a series of interviews with the producers of The Jinx, Andrew Jarecki and Marc Smerling.

The amount of press coverage Durst has generated is topped only by the volume of work he has made for his lawyers and police investigators in Westchester, Los Angeles, Galveston and beyond. Yet he had rebuffed overtures from journalists until he saw All Good Things, a lightly fictionalised film the producers had previously made of his life in 2010.

NEW YORK TIMES NEWS SERVICE