LOS ANGELES — Prosecutors in the Los Angeles murder case against eccentric New York real estate heir Robert Durst want his victim's words to help send him to prison.

Prosecutors filed nearly 400 pages of documents Friday to argue that statements Susan Berman made to friends before she was killed in 2000 should be allowed to help prove that Durst knocked her off to silence what she knew about his first wife's mysterious 1982 disappearance.

Defense lawyers have argued the statements are hearsay and inadmissible.

But Deputy District Attorney John Lewin said Durst forfeited the right to challenge the statements because he killed Berman to prevent her from being a witness.

"Silence, like a cancer, grows," Lewin wrote, borrowing a lyric from Simon and Garfunkel's "Sounds of Silence." ''Faced now with the prospect of at long last being brought to justice, defendant tries again to prevent Susan's voice from being heard. His attempt to prohibit the jury from learning what she said about him killing his wife is the most recent chapter in defendant's 36-year quest to evade responsibility for the heinous crimes he has committed."

Berman told friends that the real estate tycoon admitted he killed Kathleen Durst, who was a medical student when she vanished. Her body has never been found, but she was officially declared dead last year.

Berman also told several friends, including former "Saturday Night Live" cast member Laraine Newman, that she provided alibis for Durst, her good friend.

Durst, 74, has pleaded not guilty and has denied any part in her fatal shooting. Berman, a writer who was the daughter of a Las Vegas mobster, had been best friends with Durst since they were undergrads at the University of California, Los Angeles in the 1960s.

The filing comes as lawyers in the case prepare for a preliminary hearing next month in Los Angeles Superior Court that will determine if Durst stands trial on a murder count in Berman's death.

It also marks what is likely to be a contentious fight over the admissibility of a wide range of evidence from hearsay witness statements, including those made by Durst, to Lewin's lengthy interrogation of Durst after his arrest in New Orleans in 2015 that came just before the final episode aired of the six-part HBO series "The Jinx: The Life and Deaths of Robert Durst."

Durst is also expected to try to prevent jurors from seeing clips from that project, including the dramatic finale when he was caught on a live microphone muttering: "You're caught! What the hell did I do? Killed them all, of course."

Witnesses have testified at a series of pretrial hearings that Berman, despite her close friendship with Durst, feared him and told some of them that if anything happened to her he would be responsible.

Nathan "Nick" Chavin, a mutually close friend of Durst and Berman, dropped a bombshell during one pretrial hearing when he testified that Durst admitted to him after a dinner in New York that he killed Berman.

"I had to," Durst said, according to Chavin. "It was her or me, I had no choice."

Durst, who is being held in jail, previously beat a murder charge in the 2001 killing and dismembering of a 71-year-old neighbor in Galveston, Texas. Durst had moved there and disguised himself as a mute woman to escape investigators who wanted to talk to him after reopening the investigation into Kathie Durst's disappearance.

While conceding he chopped up Morris Black's body and tossed it in the sea, Durst was acquitted of murder after testifying that he did it in self-defense.