Robert A. Durst, the estranged member of a prominent Manhattan real estate family, will not be going to Los Angeles anytime soon to face murder charges.

Mr. Durst, who turns 72 next week, was formally indicted on Wednesday on state gun charges in New Orleans. He remains in a psychiatric jail outside that city. The United States attorney in New Orleans also filed a federal gun charge against him this week.

But while the case in Louisiana plays out, prosecutors and investigators from California will be in New York next week to interview additional witnesses as part of their expanding investigation into what they now believe was Mr. Durst’s execution-style murder of a close confidante, Susan Berman, in Los Angeles 15 years ago.

Mr. Durst’s lawyers contend that the charges in New Orleans are part of a collaborative effort by the authorities to allow Los Angeles to continue to prepare their case while depriving the defense of its right to learn what evidence they have.