Robert Durst murder trial: Susan Berman 'knew her killer,' prosecutors say Durst's close friend, Susan Berman, was found dead in her home in 2000.

Los Angeles prosecutors are expected to call more than 100 witnesses to prove that New York real estate heir Robert Durst killed his close friend Susan Berman in cold blood.

Berman's body was found in her home on Dec. 24, 2000. She had been shot execution-style in the back of the head.

"Evidence is going to show Susan knew her killer and she freely and voluntarily admitted this person into her house," Deputy District Attorney John Lewin said during his opening statements Wednesday.

Lewin intends to prove that Berman was "unafraid" of her killer and had her back turned when she was shot to death.

Durst was arrested for Berman's murder in 2015 -- one day before the last episode of the HBO series "The Jinx: The Life and Deaths of Robert Durst" aired. The 2010 interviews with Durst that were used in the six-part series were played throughout the opening statements.

Prosecutors allege Robert Durst wanted to silence Berman about the 1982 disappearance of his first wife, Kathleen Durst.

The 76-year-old had an "unequal" relationship with Kathleen Durst and would repeatedly have affairs, Lewin said. Robert Durst said in interviews for the HBO show that he gave his wife "a small budget," but when she decided to go to medical school, he cut her off and forced her to take out loans.

Robert Durst was investigated but never charged. His wife's body was never found.

Berman -- a close friend of Durst's since their UCLA days -- allegedly helped Durst with an alibi after Kathleen Durst vanished.

Berman was about to meet with investigators about the Kathleen Durst case when she was killed at her house in Beverly Hills. A gruesome photograph of Berman's body laying face up in what Lewin described as a "small pool of blood" was shown to the jurors.

"One of the things that will become very clear is that much of damaging evidence will come from Mr. Durst's own mouth," said Lewin as a disheveled Robert Durst sat at the defense table and fiddled with a hearing aide in his right ear.

Robert Durst's lawyers claim he did not kill Berman and doesn't know who did.

Lewin gave the jurors a timeline of Robert Durst's "I can do whatever I want" attitude including his admission to signing up for and using food stamps.

Another piece of evidence revealed in the "The Jinx" was a letter producers found that Durst once wrote to Berman, in which "Beverly Hills" was misspelled as "Beverley." Police were led to the discovery of Berman's body back in 2000 because of a note with Berman's address and the word "cadaver" on it. That note to police had the same "Beverley" misspelling and both notes had nearly identical handwriting.

This won't be Durst's first time on trial.

Durst was charged in the 2001 killing of neighbor Morris Black in Galveston, Texas, but Durst claimed he shot him in self-defense and was found not guilty.

Durst admitted to chopping up Black's body and disposing of the pieces in the sea.