Real estate scion Robert Durst’s carelessness could ultimately lead to his downfall as he lost track of the countless lies he told over the years, prosecutors argued in their opening statements on the third day of the rebooted trial. 

Deputy District Attorney John Lewin wove a mix of Durst’s sometimes contradictory statements to outline evidence that he said will show the New York real estate heir killed his best friend and a neighbor to cover up the mystery of his wife’s disappearance.

"One of the hallmarks of Bob Durst is that despite all the lies he tells, he doesn’t take or use the mental energy to even remember them because his life has been spent privileged in getting away with whatever he wants," Lewin said. "The evidence is going to show that’s going to be his undoing in a lot of ways in all three of these cases."

Durst, 78, has pleaded not guilty to one count of murder -- the killing of his best friend, Susan Berman, in 2000 in her Los Angeles home. Durst's lawyers have previously said he didn't kill Berman and doesn’t know who did. 

The septuagenarian, who suffers from myriad maladies, was slumped in a wheelchair and dressed in a blue sport coat, white dress shirt and tan pants. His gray hair was disheveled and he appeared to show no emotion behind a white mask as he followed the proceedings on a tablet computer that provided a real-time transcript because he has impaired hearing.

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Berman was his longtime confidant and once an unofficial spokeswoman when Kathie Durst vanished in New York in 1982.

Lewin said the killing of Berman, who was shot in the back of the head at close range, and Durst’s admission that he fatally shot and dismembered a drifter in Texas in 2001 are both tied to the mystery of Kathie Durst.

"Everything starts with Kathie Durst’s disappearance and death at the hands of Mr. Durst," Lewin said.

Lewin provided an abbreviated opening statement to refresh jurors on what they last heard over six days in March 2020 before the case was recessed an unprecedented 14 months because of the coronavirus pandemic. Before the trial was halted, defense attorneys shocked the audience when they said they would put Durst on the witness stand. 

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Later Wednesday, the prosecution heard from two witnesses: LAPD Officer Rashad Sharif, who found Berman's body, Dr. Sophie Balk, who ran the pediatric clinic where Kathie Durst worked in 1982, and Riverside County's chief forensic pathologist Mark Fajardo. 

At the time Durst was arrested in New Orleans in 2015, Fajardo ran the Los Angeles coroner's office. He testified previously that at the time, he reviewed the report on Berman's December 2000 autopsy – the pathologist who originally conducted Berman's autopsy has retired. 

Berman was found dead in her Benedict Canyon home in December 2000. Police were directed to the home by a note with only her address and the word, "CADAVER" written in block letters.

Robert Durst, wealthy NY real estate heir, was arrested in March 2015 in connection with the murder of his friend Susan Berman. (Francine Orr/ Los Angeles Times via Getty Images)

Durst told the makers of "The Jinx: The Life and Deaths of Robert Durst" in 2010 and 2012 that he didn’t write the note. He told the filmmakers and investigators in 2015 that whoever wrote the note had to have been Berman’s killer.

"You’re writing a note to the police that only the killer could have written," Durst said.

Lewin said that now amounts to a confession after defense lawyers conceded before trial that Durst wrote the note. Evidence had shown he once penned a note to Berman in identical handwriting, with her address similarly misspelled "Beverley" Hills instead of Beverly.

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The defense argues Durst found Berman’s body, panicked and ran. He sent the note to police so she’d be found, though her body was discovered before police got the note.

Durst killed Berman to keep her from talking to police about how she helped him cover up his wife’s disappearance, Lewin said.

Deputy District Attorney John Lewin begins opening statements in the trial of Robert Durst, the real estate scion charged with murder of longtime friend Susan Berman, at Los Angeles County Superior Court, Tuesday, May 18, 2021, in Inglewood, Calif. (Al Seib/Los Angeles Times via AP, Pool)

Lewin played a clip of testimony from Nick Chavin, a mutually close friend of the defendant and victim, who said Berman once told him that Durst had killed Kathie. In 2014, after having dinner in New York, Durst told Chavin he killed Berman.

"I had to," Durst said on the sidewalk outside the restaurant before parting ways, Chavin said. "It was her or me, I had no choice."

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Lewin said Berman, the daughter of a Las Vegas mobster who never would have turned her back on a stranger, had no idea Durst had come to kill her when she let him in her home just before Christmas.

"She turned around because she trusted him, because he was her close friend, because he was not somebody to fear," Lewin said. "She turned around, she took a few steps and he basically blew her brains out."

Fox News' Bradford Betz and The Associated Press contributed to this report.