But even as the family celebrates the founding of the Durst Organization 100 years ago by its patriarch, Joseph Durst, Robert casts a long, dark shadow.

Image Douglas Durst Credit... Michael Appleton for The New York Times

Now 72 and frail, Mr. Durst is scheduled to be in court in New Orleans on Dec. 17 for sentencing on a gun charge. Sometime next summer he will be transferred to Los Angeles, where he has been accused of murdering a former confidante, Susan Berman, who was found shot in the back of her head at her home on Dec. 24, 2000. Prosecutors say Mr. Durst wanted to ensure that Ms. Berman would not reveal what she knew about the abrupt disappearance of his first wife, Kathleen Durst, in 1982. In another case riddled with bizarre twists, Mr. Durst, who had been living on the cheap in Texas as a mute woman, admitted to butchering his neighbor’s body and dumping the parts into Galveston Bay. He claimed that the neighbor’s death had been accidental, that he had been acting in self-defense. A jury acquitted him of murder in 2003.

The Los Angeles trial, which will pit his multimillion-dollar defense team against a prosecutor who specializes in cold cases, promises to attract the kind of intense media interest that, once again to the family’s chagrin, will eclipse the Dursts’ legacy on the New York skyline.

Douglas expects to be a witness for the prosecution.

Of his brother, with whom he has had a tempestuous relationship since they were boys, Douglas would say very little. “Bob has always been a burden for me and my immediate family,” he said, “but it has not impacted our relations with others or the Durst Organization’s ability to do business.”