NEW YORK – The state murder trial of Luigi Mangione in the killing of UnitedHealthcare CEO Brian Thompson will not begin as planned on Sept. 8, after a judge postponed the case indefinitely while defense attorneys argue it should be dismissed on double jeopardy grounds following Mangione’s federal guilty plea last week.

Judge Gregory Carro on Monday canceled the trial date and set a briefing schedule, giving the Manhattan District Attorney’s office until Oct. 9 to answer the defense motion. Carro also scheduled a Dec. 10 hearing on the issue, roughly one week before Mangione is due to be sentenced in the federal case.

Mangione, 28, pleaded guilty Friday in Manhattan federal court to two stalking counts, admitting that he followed Thompson to a UnitedHealth Group investor conference and fatally shot him outside a Manhattan hotel in 2024. Federal prosecutors have said they will ask for a life sentence at Mangione’s Dec. 18 sentencing, although federal guidelines recommend a prison term of 24 to 30 years.

“On the morning of Dec. 4, 2024, I shot Mr. Thompson in Manhattan, and he died,” Mangione said.

Soon after entering the plea, Mangione’s defense team moved to dismiss the state prosecution, arguing that continuing the case would violate double jeopardy and due process protections. In their filing, the lawyers called Mangione a “pawn in parallel prosecutions” and claimed state and federal authorities are “trying to punish him twice for the exact conduct.”

Mangione has pleaded not guilty to the state charges, which could also result in a life sentence if he is convicted.

The office of Manhattan District Attorney Alvin Bragg said it intends to oppose the bid to dismiss the state case, noting in part that Mangione’s federal sentence has not yet been determined.

New York law gives defendants unusually broad protection against multiple prosecutions when compared with federal law and the laws of many other states. A state case may be blocked if a federal prosecution tied to the same conduct or criminal transaction has ended with a guilty plea or once a jury has been sworn.

It will be up to Carro to decide if that applies to Mangione. However Carro rules, his decision will be subject to appeal.

Mangione pleaded guilty to federal charges that accused him of traveling across state lines by bus to stalk and kill Thompson. The charges alleged that he used a cellphone, the internet, interstate highways and a hostel serving out-of-state customers to plan and carry out the attack.

“The full range of conduct that comprises the stalking offense is coterminous with the conduct committed as part of the murder offense,” Mangione’s lawyers wrote in their double jeopardy filing.

That Mangione traveled from out of state “to be at the crime scene at the time of the shooting does nothing to eliminate the stalking of Mr. Thompson from the acts constituting his murder,” they added. “They are all part of the same criminal incident or criminal transaction.”

Bragg’s office contends that the state charges, including murder and firearms offenses, involve different legal elements and criminal conduct. In a letter last month, Assistant District Attorney Joel Seidemann objected to the possibility of a federal guilty plea wiping out the state case.

Any guilty plea, Seidemann wrote, “must account for the seriousness of defendant’s offenses” and for the state’s interests in prosecuting Mangione, “including the sanctity of life principle that underpins the state homicide charges.”