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A New York City detective who investigated the disappearance of real-estate heir Robert Durst's wife testified Tuesday that neighbors told him about a disturbing incident in which the missing woman claimed her husband "wanted to kill her."

Durst, the subject of the HBO series "The Jinx," is set to stand trial in Los Angeles for the murder of confidante Susan Berman in 2000. Prosecutors contend he killed her because he was worried she would implicate him in the death of his first wife, Kathie, who vanished in 1982.

Real estate heir Robert Durst, right, has a lighter moment with his attorney Dick DeGuerin while appearing in court in January. Mark Boster / AP file

During a pre-trial hearing, ex-cop James Varian, 77, read from a decades-old report he and his partner wrote about their investigation, including an interview with Kevin and Anne Doyle, who lived across the hall from the Dursts in a Manhattan apartment building.

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Varian said the Doyles recalled that at one point before she vanished, a pajama-clad Kathie Durst had climbed out of her apartment onto a balcony and knocked on their window.

She told the couple "Bob had beat her and he wanted to kill her," Varian's report said. She also claimed that her husband "had a gun and [she] was afraid of being shot" and that she had hid in a bathroom for two hours.

The retired detective said Kevin Doyle spoke to Robert Durst, who denied being mad at his wife and did not admit to beating her.

Varian is one of a string of witnesses that prosecutors have brought to the stand to make sure their testimony is recorded before a trial that is still months away. The judge has not yet ruled on whether the jury can hear the accounts of Varian and the other witnesses.

Among those expected to testify this week is one of the district attorney's two so-called secret witnesses, whose identity is kept secret until they enter the courtroom.

In February, the first secret witness, advertising executive Nick Chavin took the stand and delivered damning testimony, claiming Durst admitted killing his first wife and intimated that he also killed Berman.

Chavin — who was a close friend of both suspect and victim — said that after a dinner in 2014, he asked Durst about Berman's slaying.

"It was her or me," Durst allegedly replied.

Chavin also testified that when Kathie Durst went missing, Berman told him: "Bob killed Kathie." She claimed Durst confessed and said it was an accident, Chavin testified.

Durst has denied killing either woman. Suspicions about his involvement were examined in "The Jinx," which ended with his bombshell comment on a hot microphone that he had "killed them all."