A "secret witness" who fears for his life is expected to testify Wednesday against New York real estate heir Robert Durst in a California murder case.
The testimony, which comes at a special hearing even before a judge has decided whether Durst should stand trial, will be recorded on video. It would only be used if something happens to him and he can't testify during a potential trial.
Prosecutors have suggested the eccentric millionaire could have witnesses killed and they don't plan to reveal the man's identity until they call him to the stand.
The defense was told his name two weeks ago.
Prosecutors contend that Durst killed his best friend Susan Berman in 2000 because he thought she was going to talk to police about the 1982 disappearance of his wife, Kathie Durst, who was never found.
A similar conditional witness giving advance testimony to be used at trial if necessary took the stand on Tuesday, and his testimony centered on the wife.
Dr. Albert Kuperman, 85, a retired associate dean at Albert Einstein College of Medicine, testified that Kathleen, was a bright, attractive, smartly dressed medical student.
On Feb. 1, 1982, Kuperman got a call from a woman who identified herself as Kathie Durst and said she was sick with diarrhea and a headache and wouldn't make it to her first day of a pediatrics clerkship in her final year of medical school.
The call was long believed to be the last conversation anyone had with Kathie Durst. But Deputy District Attorney John Lewin suggested while interrogating Durst two years ago that someone else placed the call.
Durst told Lewin that filmmakers who interviewed him extensively for the six-part HBO series "The Jinx: The Life and Deaths of Robert Durst" thought Berman posed as Kathie Durst on the call. Durst disputed that and said Berman never would have made the call.
Durst was arrested two years ago on the murder charge in New Orleans just before the final episode of "The Jinx" aired in which he is heard muttering to himself on a live microphone: "You're caught! What the hell did I do? Killed them all, of course."
Durst, 73, has denied killing the women, and his lawyers have said it's absurd to suggest he could have witnesses knocked off. He has pleaded not guilty to one count of first-degree murder.
Berman and Durst had been close friends since they attended the University of California, Los Angeles. She acted as Durst's unofficial spokeswoman after his wife's disappearance.
Durst, who is frail and hunched, walked into court Tuesday after making previous entrances in a wheelchair.
Judge Mark Windham won't decide until a preliminary hearing, tentatively scheduled for October, whether Durst even goes to trial.
Kuperman testified throughout the day as Deputy District Attorney Habib Balian tried to show Kathie Durst was a good student who was close to graduating and making career plans in medicine.
But defense attorney Dick DeGuerin provided records showing she had a spotty attendance, had dropped out of three clerkships in one year and her absences had drawn the attention of a fellow dean.
Kuperman, who has been interviewed by various detectives and prosecutors over three decades, said it was strange Kathie Durst called him and not the chief resident of the clerkship she was to start that day. But until recent years when he was re-interviewed, he had never questioned that it was her on the phone.
Asked by DeGuerin if Lewin had planted that seed of doubt, Kuperman replied: "I think that's when it began to gel."