In a 2015 recorded jail call, real estate heir and murder suspect Robert Durst told a friend he regretted participating in the HBO documentary “The Jinx,” saying that while he was watching the six-episode series, he realized he “definitely” had a problem.

According to the Los Angeles Times, prosecutors played the jail call during a court hearing on Thursday. Durst told his friend that he became concerned while watching the fifth episode of the documentary, in which producers show a letter Durst sent to his best friend Susan Berman that had similar handwriting to an anonymous letter sent to police at the time of Berman’s death. In both letters, Beverly Hills is misspelled as “Beverley Hills.”

In another jail call played by prosecutors, Durst said, “If I can find somebody who’s got something I wrote back then, or even somebody who can say, ‘Yeah, yeah, Bob used to write to me. He wrote me a couple of letters. He never misspelled Beverly,’ that would be very helpful, I think.”

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Prosecutors contend that Berman, whose body was found on Christmas Eve in 2000, was killed to prevent her from revealing incriminating information about Durst’s involvement in the disappearance of his wife Kathleen in 1982. The case still remains unsolved.

While the now 75-year-old Durst has denied killing either woman, the last episode of “The Jinx” saw Durst mumble, “What the hell did I do? Kill them all, of course.” To many, that was a confession to killing Berman, Kathleen and Morris Black, his former neighbor in Galveston, Texas. Durst formerly admitted to shooting the latter in 2001 in an act of self-defense. He also admitted to chopping up his body and dumping the body parts in Galveston Bay — he was acquitted.

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Durst was arrested March 14, 2015 in connection with the murder of Berman, on the day before the final episode of “The Jinx” aired. In 2016, the Los Angeles District Attorney said it would not seek capital punishment for the execution style killing of Berman. Durst was held without bail, with a preliminary hearing scheduled for Feb. 15, 2017.

Durst was transferred to Southern California from Louisiana, where he was being held on weapons charges after pleading guilty in February 2016, which resulted in a seven-year, one-month federal prison sentence.