Defense attorneys in the upcoming New York State murder trial will no longer be using a psychiatric defense for Luigi Mangione, the young man accused of gunning down UnitedHealthcare CEO Brian Thompson in the streets of Manhattan in December 2024.

The day after a judge announced that Mangione’s defense team intended to argue that he was experiencing an extreme emotional disturbance at the time of the slaying, the defense withdrew their plans, citing it would have been difficult with the federal trial.

Slaying of The UnitedHealthcare CEO

On December 4, 2024, Thompson was seen leaving a hotel in Manhattan, New York, for an annual healthcare conference. He was approached by a masked man behind and shot at close range in the back. 

While the gunman was not identified through surveillance footage of the crime scene, a five-day-long manhunt led officers to their suspect at a McDonald’s in Altoona, Pennsylvania.

Felony Charges

At that McDonald’s, they found Luigi Mangione, who is charged with eight felony counts, including second-degree murder and stalking, for which he has pleaded not guilty. His defense previously floated the idea of using a psychiatric argument in his state trial, but upon further discussion, they found it would be harmful to his federal case.

If they were able to prove Mangione’s emotional disturbance at the time of the killing, his possible conviction could have been reduced to first-degree manslaughter. 

Luigi Mangione’s Psychiatric Defense

State Supreme Court Judge Gregory Carro has been the presiding judge in this case since the beginning, and, at the defense’s request, he sealed medical information at a hearing earlier this month, saying it would be “very prejudicial” to the defense if they decided not to proceed with the psychiatric defense.

On Wednesday, Assistant District Attorney Joel Seidemann argued that by not sharing the information related to their emotional disturbance claims, it was impeding their ability to properly try the defendant. 

Carro ordered Mangione’s defense attorneys to release the information no later than Thursday, and he said he would unseal records related to the psychiatric argument. 

“(Prosecutors) need to know what the malady is that this defendant suffers and how that triggered an extreme emotional disturbance at the time and place of the occurrence,” he said. “Nothing is going to be a surprise. I’m not going to let you surprise the People on the eve of the trial. So, get it done.”

However, come Thursday, Carro said they would not be unsealed. In a released court transcript, Mangione’s defense team explained that logistical issues in the federal case would make it difficult to present their psychiatric argument. Some of their experts have even refused to cooperate with the case due to its infamy.

Outrage Fueling The Nation

The state trial is scheduled to begin in early September, with the federal trial following closely behind. Initially, the state trial was set to begin in June 2026, but the defense requested more time, resulting in both trials being delayed.

The killing of the chief executive of the country’s largest health insurer led to nationwide outrage. Many were consumed with hate towards the industry and were proud of what the accused allegedly stands for. Authorities quickly began making examples out of anyone who dared to threaten healthcare officials.

Depending on the outcome of the trials, the country and its healthcare companies may face a much more severe backlash, with many arguing that Mangione is an easy target and that he was right for what he allegedly did.

Key Piece of Evidence

Prosecutors say that Mangione had a manifesto that detailed his plans to kill UnitedHealthcare’s CEO. They said the intent was to introduce the red notebook discovered in the defendant’s backpack as a piece of evidence during his trial. It allegedly tells you how to “rebel against the deadly, greed fueled health insurance cartel.”

According to a filing from the district attorney’s office, the contents of the notebook, or as prosecutors call it “the diary,” state he intended to “Wack the CEO at the annual parasitic bean-counter convention.”

“It’s targeted, precise, and doesn’t risk innocents,” the diary says.

Mangione’s defense initially sought to prevent the diary from being used as evidence, arguing that authorities obtained it during an illegal search of his person at the fast-food chain. However, Judge Carro disagreed and allowed prosecutors to proceed.