INGLEWOOD, Calif. (CNS) — New York real estate scion Robert Durst testified Monday in his murder trial that he sent police a letter informing them about a "cadaver" after going to a longtime friend and confidante's Benedict Canyon house and finding her dead on the floor. 

In his fourth day on the stand, the 78-year-old defendant said he found Susan Berman "just lying there," and thought she had fallen or fainted and struck her head or been hit in the back of the head.

"I did not imagine at that time that she had been shot," said Durst, who has denied being involved with the 55-year-old writer's December 2000 shooting death.

He said he unsuccessfully tried to call 911 from a landline phone in the home that was dead, then drove to a pay phone to make a 911 call and realized his voice would be recognized even if he gave a fake name. He said he opted instead to send Beverly Hills police a letter informing them about the "cadaver" at Berman's home.

"Did you write that letter?" Durst's lead attorney, Dick DeGuerin, asked his client.

"Yes, I did," Durst responded.

"Did you lie about it for years?" DeGuerin asked.

Durst responded that he had lied about it because "it's a very difficult thing to believe" that he wrote it but "did not kill Susan Berman."

He said he had "no reason" to kill his longtime friend, but "someone must have had a reason and a motive to kill Susan Berman."

In his opening statement last year, DeGuerin told jurors that his client "showed up and found her dead" and "panicked."

"Bob Durst did not kill Susan Berman and he does not know who did," DeGuerin said in May when the trial resumed after being stalled for more than a year by the COVID-19 pandemic.

DeGuerin disputed the prosecution's contention that Berman made a phone call posing as Durst's first wife, Kathie Durst, after she disappeared in 1982, and called Berman a  "storyteller" who had a "great imagination" and "made things up."

Deputy District Attorney John Lewin told jurors in his opening statement the evidence would show that Durst shot and killed Berman "out of survival" just before Christmas in 2000 because he feared she would tell authorities about his involvement in Kathie Durst's disappearance.

During his updated opening statement in May, Lewin called the cases of Kathie Durst and Susan Berman "interrelated," and told jurors they would hear evidence that Durst killed his wife and used Berman to help cover up his part in the crime, and that he subsequently had to kill his neighbor, Morris Black, in Galveston, Texas, in 2001, because the man figured out who Durst was and was putting pressure on him.

Durst was acquitted of murder in Texas after testifying that he killed Black in self-defense in September 2001.

Durst has been behind bars since March 14, 2015, when he was taken into custody in a New Orleans hotel room hours before the airing of the final episode of the six-part HBO series, "The Jinx: The Life and Deaths of Robert Durst," which examined Kathie Durst's disappearance and the killings of Berman and Black. 

DeGuerin has told the panel that the series — in which the defendant was recorded saying "There it is, you're caught" and "killed them all, of course" — was "heavily edited" and "not a documentary."

Durst has been long estranged from his real estate-rich family, which is known for ownership of a series of New York City skyscrapers — including an investment in the World Trade Center.

Durst split with the family when his younger brother was placed in charge of the family business, leading to a drawn-out legal battle, and ultimately reached a settlement under which the family reportedly paid him $60 million to $65 million.