The bombshell testimony took place during a pre-trial hearing in Los Angeles, where advertising executive Nick Chavin is testifying ahead of Durst’s murder trial in the 2000 slaying of Susan Berman.
Prosecutors allege Durst killed Berman, his close friend, because she knew too much about the 1982 disappearance of his first wife, Kathleen.
Durst pleaded not guilty in Berman’s death.
In court Thursday, Chavin testified that Berman told him Durst admitted to killing Kathleen — but Chavin didn’t initially didn’t initially believe her.
When he asked why she thought Durst had committed the crime, Berman told Chavin that Durst had confessed to her, he testified.
Chavin said he and Berman had a few conversations about Kathleen’s death. He testified that Berman would say that there wasn’t anything they could do for Kathleen and they had to protect Durst.
“Kathie is gone. We need to protect him,” Chavin testified Berman told him.
He added, “It was certainly mentioned on several occasions, and then we stopped talking about it.”
Chavin also testified he never asked Berman for details of the alleged confession and that he didn’t want to know them.
He added that Durst and Susan were close and that Durst confided in her, saying, “He confided more with Susan than with me.”
“My relationship with Bob was close — I couldn’t believe he would commit a crime like that,” he testified.
Chavin testified that after Berman’s death, he began to ponder Durst’s possible involvement in Berman’s death and Kathleen’s disappearance.
“I certainly thought about it a great deal and I began to doubt my own feelings,” he said. “It seemed to me there was no one else that had any reason to harm Susan Berman.”
Chavin said he never went to authorities but said that New York police came to speak with him after Berman’s murder, and that he told authorities what Berman had told him.
He testified that he told New York detectives that it was easier for him to believe Kathleen was killed by a drug dealer than by Durst.
“I believed there was a photograph of Kathie with a tall Latin American man and it just seemed more probable. I believe she had a bit of a drug problem,” Chavin testified.
On the stand he described a dinner he had with Durst in New York City in 2014, after Durst had called him to say he wanted to talk about Berman and his first wife.
“I believed the only thing it could be about was the unanswered question about whether he was responsible for Kathie’s disappearance and the death of Susan Berman,” Chavin testified.
He said they didn’t end up talking about Berman or Kathleen at dinner, but when they were leaving Chavin said he decided to ask Durst about it.
“I said, ‘You wanted to talk about Susan,’ and Bob said, ‘I had to, it was her or me. I had no choice,’ ” Chavin testified. “He then turned to walk away, and I said, ‘You wanted to talk about Kathie,’ and he kept walking away and nothing more was said.”
“I think it was fair to say I wasn’t surprised,” Chavin remembered. “I was not shocked, but my response was more like ‘now I know.’ We didn’t discuss Kathie’s disappearance.”
Asked by prosecutor Lewin how he felt about testifying, Chavin responded: “I feel like it is something I had to do.”
He testified on Wednesday that Kathleen feared Durst before she disappeared.
“She never said he would hurt her, but she was afraid of him,” he said.
This article originally appeared on PEOPLE.