A "secret witness" was called, flanked by bodyguards after the prosecutor said the witness's life was in danger.
An attorney joked that the waiting period for the case to be tried might last longer than the Trump administration.
A member of the defense, pointing to his wife in the audience on Valentine's Day, provoked an objection from the prosecution: "Our wives are not here!"
But despite the sometimes jovial setting, this is still a murder trial.
The real estate heir is charged with first-degree murder of his longtime associate, Susan Berman, in 2000.
Prosecutors believe Durst killed Berman because she was about to talk to investigators about another unsolved case -- the 1982 disappearance of Durst's wife, Kathleen.
Durst was also charged in the 2001 death of his neighbor in Galveston, Texas.
In that case, Durst was acquitted after claiming he accidentally shot the man in a scuffle, then chopped up his body in a panic.
The tales of death and misfortune surrounding people close to Durst were partly why the prosecution sought this week's hearing to interview at least one witness.
"That man (Durst) kills witnesses," argued Deputy District Attorney John Lewin at a hearing in January. "Mr. Durst, when pushed into a corner, he murders people," Lewin said.
Defense attorney David Chesnoff called that "inflammatory."
"By suggesting a man in a wheelchair is somehow a threat ... is just hyperbole," he said.
This week's pretrial hearing is the result of those loud claims. Judge Mark Windham said Wednesday he allowed the early testimony of some witnesses because of their age. Prosecutors alleged that with his millions of dollars, Durst, at 73, could pay to have someone killed.
While questioning a "secret witness," revealed to be Nathan "Nick" Chavin, a friend of Durst, Lewin pointed to two men accompanying Chavin.
"The two men, seated in the jury box, they are security detail officers," he said.
"Objection! This is a blatant attempt to play to the press!" defense attorney Dick DeGuerin said.
Later, as the hearing wrapped up, DeGuerin tried to get his own rebuttal onto the notepads of reporters:
"Mr. Durst did not kill Susan Berman, and doesn't know who did!"
A life under suspicion
To prosecutors, Durst has been carrying around "motive" for 35 years.
Durst admitted at trial that he fatally shot his neighbor, Morris Black, in Galveston, Texas, in 2001 and carved up the body, dumping the dismembered corpse into a nearby bay. Durst argued that he killed Black in self-defense. Prosecutors at the time accused Durst of plotting to steal Black's identity and hide from authorities who were investigating another crime: the disappearance and presumed death of Durst's wife, Kathleen, on January 31, 1982.
When Durst was accused of shooting Berman to death in 2000 in her Beverly Hills home, prosecutors alleged it was to quiet his close friend and associate. In November, Durst told the court he didn't do it.
"I do want to say here and now, though, I am not guilty," he said. "I did not kill Susan Berman."
And if Los Angeles County prosecutors are going to succeed where others have not, they must prove that Durst spent half his life hiding an awful secret about his wife's disappearance.
This week's hearing was their first shot.
Chavin, the "secret witness," who said Durst was the best man at his wedding, told the court of marital problems festering until Kathleen "said she was afraid of him."
"On one occasion she cried," Chavin said. "She was appealing to me as Bob's friend to understand she was having a terrible time with her marriage."
Durst claims the last time he saw his wife was after she boarded a train in their suburban New York hometown, headed for the city to resume her studies at Albert Einstein College of Medicine in the Bronx.
Prosecutors claim she never got on that train. They say Durst killed her and asked Berman to help cover up the crime.
"Susan would tell me how much she loved Bobby," Chavin said.
"Given the closeness of Bob and Susan's relationship," asked prosecutor Lewin, "Is there anything you can think of that Susan would not have done for Bob?"
"No," Chavin said. "Not if it were within her ability to do it."
Including, prosecutors insinuated, impersonating a dead wife.
A mysterious phone call
On the first day of Kathleen Durst's radiology clerkship in 1982, Dr. Albert Kuperman of the Einstein College of Medicine got a phone call from a woman. It was thought to be the last time anyone heard from Kathleen.
"The woman stated she would be absent from the clinical duties she was assigned to that day," said Kuperman, 85, testifying early because of his age. "And I asked her why, and she said she had GI distress, gastrointestinal distress."
The problem for prosecutors: The call was placed on February 1, 1982 -- one day after Kathleen was supposedly killed.
Kuperman, who generally spoke to Kathleen only in person, now admits he has no reason to believe it was her on the phone, other than the caller saying so.
"You never talked to her on the phone before, never heard a recording of her?" prosecutor Habib Balian asked.
"Yes," Kuperman said, admitting he had not.
DeGuerin, Durst's defense attorney, argued that Kuperman only waivered on the certainty of the caller's identity after being questioned by investigators in 2015.
"What you told the movie producers (of HBO's 'The Jinx') was that you felt like the police were trying to get you to change your story," DeGuerin said.
"Yes," Kuperman replied, explaining that he didn't feel pressured by investigators, only that "they wanted me to be sure that it was indeed Kathleen Durst who called me."
To prosecutors, the significance of the call is less about Kathleen and more about Berman.
Could it have been someone else on the line -- possibly even Berman?
That theory got bolstered this week when Nathan Chavin connected several dots for the prosecution. First, testifying that Berman told him Robert Durst killed his wife. Then, saying Durst confessed to him in 2014 that he killed Berman to keep her quiet.
"I had to. It was her or me," Durst said, according to Chavin, as reported by the Los Angeles Times. "I had no choice."
The defense has called Chavin less than reliable, indicating they may try at trial to call to the stand a New York Times reporter who interviewed Chavin. The defense believes Chavin's interview with the Times might conflict with his testimony.
Despite this week's drama, the Durst case is still in its infancy. A preliminary hearing isn't expected until later this year.
A trial likely wouldn't come until 2018.
On consecutive days this week, Durst -- who has shed his wheelchair and now walks into court under his own power -- turned in his chair to scan the 50 or so spectators in the courtroom.
If he was nervous, it didn't show. After all, Durst has been here before. And he has yet to lose.