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.