LOS ANGELES — It is perhaps fitting that the defense team for Robert A. Durst, the one-time heir to a Manhattan real estate empire who is on trial for murder, is now ensconced in the luxurious Peninsula Hotel in Beverly Hills.

It was over breakfast at that hotel in 2010 that Mr. Durst made the fateful decision to cooperate with a filmmaker, Andrew Jarecki, ultimately agreeing to provide more than 20 hours of interviews and access to 60 cartons of his personal papers.

His decision to break his silence at the hotel — after nearly four decades of being trailed by suspicions that he was involved in the deaths of three people in three states — led in no small way to an HBO documentary, “The Jinx: The Life and Deaths of Robert Durst,” in 2015 and his subsequent arrest on murder charges in the execution-style killing of his close friend Susan Berman in Los Angeles in December 2000.

The lawyers have established a war room at the hotel to plan their defense of Mr. Durst against the prosecution’s contention that their client executed Ms. Berman because he was afraid that she was about to reveal to the authorities her role in helping him cover-up the disappearance and murder of his first wife, Kathie, in 1982.