LOS ANGELES (Reuters) - A frail-looking Robert Durst appeared in a Los Angeles courtroom on Monday for the start of a hearing to determine if the real estate scion should stand trial for the murder 18 years ago of a friend who prosecutors say could have tied him to the presumed killing of his wife.

FILE PHOTO - New York real estate scion Robert Durst appears in the Los Angeles Superior Court Airport Branch for a pre-trial motions hearing in Los Angeles, California, January 6, 2017 REUTERS/Mark Boster /Los Angeles Times/Pool/File Photo

Durst, 75, entered Los Angeles Superior Court slowly, dressed in a tan and gray suit for proceedings to assess the evidence that were expected to last several weeks.

He appeared to nod off at times during testimony by his former apartment manager, a police forensic scientist and a coroner’s investigator.

Durst, the enigmatic subject of the popular HBO documentary “The Jinx,” was charged with the murder of Susan Berman in 2015, a day after that broadcast aired its final episode.

Prosecutors say Durst fatally shot Berman, a writer and the daughter of an organized crime figure, in Los Angeles in 2000 because of what she knew about the death of his wife.

Berman, 55, was found dead at her home a few months after it was revealed that police in New York had reopened an investigation into the 1982 disappearance and presumed slaying of Kathleen Durst, his wife who was a medical student in New York when she vanished.

Durst has pleaded not guilty to first-degree murder charges stemming from Berman’s death. He also has denied having anything to do with the disappearance of his wife, whose body was never found. He has never been arrested or charged in that case.

The miniseries investigated Durst’s ties to Berman’s slaying, his wife’s unsolved disappearance and his 2003 acquittal in the slaying and dismemberment of a Texas neighbor.

In the closing minutes of “The Jinx,” Durst, the heir to a New York real estate fortune, is heard muttering to himself off-camera, “What the hell did I do? Killed them all, of course.” The documentary has provided grist for prosecutors even as defense attorneys have sought to keep the footage out of court and discredit the production as biased against their client.

In 2001, Durst, who was living at the time disguised as a mute woman, was arrested on suspicion of killing and dismembering his elderly neighbor, Morris Black.

Durst admitted during trial that he killed and carved up Black, but a jury acquitted him of homicide after he argued it was an accidental shooting in self-defense. He spent about three years in jail for related minor charges.