Attorneys for Luigi Mangione will pursue a mental health defense at his upcoming murder trial in State Supreme Court in Manhattan, the judge overseeing the case revealed at a pre-trial conference Wednesday.

Justice Gregory Carro ordered material be unsealed related to Mangione’s defense that he was extremely emotionally disturbed when he allegedly shot and killed UnitedHealthcare CEO Brian Thompson in Midtown Manhattan in 2024.

Carro instructed Mangione’s attorneys to turn over to prosecutors the name of the mental health expert they relied on as well as any report they draw up related to a mental health defense.

Carro said defense attorneys need to let prosecutors know the “malady” that their expert says Mangione was allegedly suffering that may have led him to kill Thompson.

The judge instructed the defense team to do so quickly after prosecutors suggested they may try to delay the September trial date.

“I’m not going to let you surprise the people on the eve of trial,” he told Mangione defense attorney Karen Agnifilo.

The revelation at the pre-trial hearing came after a prior hearing on the subject was sealed from the public at the request of Mangione’s defense attorneys. Carro said he ordered that hearing sealed because he didn’t want to unfairly prejudice Mangione’s defense at trial.

The judge overseeing his state case decided last month that a jury will be allowed to see several key pieces of evidence at trial, including a gun and a notebook. Prosecutors will not be allowed to show jurors a cellphone, a loaded magazine, a passport, or several other items he had with him when he was arrested, the judge ruled. Defense attorneys asked for the evidence not to be shown at trial, because they said they were found during an illegal search.

Mangione, 28, has pleaded not guilty to murder and weapons possession charges in the killing of Thompson outside a Midtown hotel in December 2024. He also faces stalking charges in federal court.

The case has garnered international attention, fueling debates about the health insurance industry, profit motives of major corporations and the public’s attitudes toward targeted violence. Social media influencers, spectators and journalists filled the seats of the 13th-floor courtroom where Mangione appeared Wednesday, as has become the norm for the high-profile figure’s court appearances.