Robert Durst just pled not guilty to murder, in the death of his good friend, Susan Berman.
Durst appeared in L.A. County Superior Court Monday afternoon to enter his plea. He was wearing a neck brace, sitting next to his lawyers.
The 73-year-old was extradited from Indiana to face charges that he killed Berman because she was wise to another murder ... involving Durst's first wife, who disappeared in 1982.
Durst was famously featured in the HBO show 'The Jinx,' in which he appeared to have confessed to the murders, saying, "Killed 'em all, of course."
The D.A. says she will not seek the death penalty.