Killer real estate heir Robert Durst wore a neck brace and was wheeled into a Los Angeles courtroom Monday to be charged in the decades-old murder of a pal.

“I do want to say here and now, though, I am not guilty,” a frail-looking Durst said in court. “I did not kill Susan Berman.”

For more than a year, the 73-year-old oddball had been awaiting extradition to California, where he’s facing trial in the 2000 murder of his friend Berman.

“We’re happy to be here,” said Durst attorney Dick DeGuerin.

He said Durst’s extradition was delayed partly because he underwent spinal surgery earlier this year while in a Louisiana prison.

LA prosecutors have been seeking to bring Durst to California since shortly after his arrest in March 2015. But he first faced a federal weapons charge in New Orleans, where he pleaded guilty in April and then began serving a seven-year prison sentence in Indiana.

His arrest came as HBO was airing the finale of its six-part documentary, “The Jinx: The Life and Deaths of Robert Durst,” which explored what happened to Durst’s wife, Kathleen, whose remains have never been found; the Berman murder; as well as his Galveston, Texas, trial for killing and then dismembering neighbor Morris Black.

DeGuerin successfully argued that Durst killed Black in self-defense, and tossed his remains into a bay in a state of shock.

At the end of “The Jinx,” Durst is shown muttering to himself that he “killed them all, I guess.”

The district attorney said she will not seek the death penalty.

With Post wire services