Durst pleaded guilty to one charge of being a felon in possession of a firearm at a re-arraignment hearing, according to Anna Christman with the U.S. Attorney's Office.
The weapons charge stems from his arrest last March at a New Orleans hotel, where investigators have said Durst had a .38-caliber revolver with him and was prepared for a life on the lam
when authorities closed in. That arrest happened the day before the final episode of "The Jinx," an HBO true-crime documentary about his life. Since then, Durst has been held without bail.
Last year authorities charged him with first-degree murder and accused him of killing his friend, crime writer Susan Berman, at her California home in 2000. He hasn't yet been arraigned in that case
, but his attorneys have maintained his innocence.
"Bob Durst did not kill Susan Berman and doesn't know who did," Durst's legal team said in a statement released Wednesday. "Bob Durst has one goal and that is to get to Los Angeles and prove his innocence in Susan Berman's death."
The guilty plea and an agreement reached with several other jurisdictions "clear the decks" for Durst's extradition to California, his lawyers said.
It's not the first time Durst has been accused of murder. In a 2003 trial, he admitted killing and dismembering a neighbor, but Durst was acquitted after arguing he acted in self-defense.
Berman was shot in the head in her Beverly Hills home in December 2000, shortly before investigators were set to speak with her about the 1982 disappearance of Durst's first wife, Kathleen McCormack Durst.
Prosecutors accuse Durst of "lying in wait" and killing Berman, a crime writer and his longtime confidante, because she "was a witness to a crime."
Durst has long maintained that he had nothing to do with Berman's death or his wife's disappearance.
But some say his mutterings picked up on a live microphone and broadcast in the HBO documentary made it sound like Durst was changing his tune.
"What the hell did I do?" Durst says from a bathroom at the end of the documentary. "Killed them all, of course."
Durst's attorney has told CNN that "The Jinx" made for great television but does not represent a search for the truth.