News|CrimeLuigi Mangione appears in court as lawyers seek to bar evidence at trialMangione faces life in prison if found guilty of murdering UnitedHealthcare CEO Brian Thompson.

Luigi Mangione, the 27-year-old who allegedly killed the chief executive of the biggest health insurer in the United States in December 2024, admitted that he had a 3D-printed gun in his backpack, a prison guard testified at a pretrial hearing in the case on Monday.

The hearing in a New York City court is part of a process that will determine what evidence prosecutors can use against Mangione, accused of shooting dead UnitedHealthcare CEO Brian Thompson .

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A defence lawyer cast doubt on the guard’s assertion that Mangione, who wore a grey suit and a white shirt with a red checkered pattern at the hearing before Justice Gregory Carro, volunteered such incriminating information on his own.

“You weren’t asking him any questions, you weren’t speaking to him at all… And out of nowhere, he says to you, ‘I had a 3D-printed pistol’?” defence lawyer Marc Agnifilo asked.

The guard said he did not ask Mangione any questions and testified during follow-up questioning by a prosecutor that he did not care about the outcome of the case.

Mangione’s purported statements to law enforcement and the contents of his backpack could be key pieces of evidence at his trial, but his lawyers argue they should be inadmissible because they say he was illegally searched and not given notice of his legal rights.

Advertisement Prosecutors deny claims that Mangione was illegally searched and questioned.

A screen displays a picture of Luigi Mangione, the suspect in the killing of UnitedHealthcare chief executive Brian Thompson, outside Manhattan Criminal Court, in New York City, on December 1, 2025 [Mike Segar/Reuters] Eliminating the gun and notebook from admissible evidence would be critical wins for Mangione’s defence and would represent major setbacks for prosecutors, depriving them of a possible murder weapon and evidence that they say points to motive.

Prosecutors have quoted extensively from Mangione’s writings in court filings, including his alleged praise for the late “Unabomber” Theodore Kaczynski , who carried out a series of mail bombings between 1978 and 1995.

Among other things, prosecutors say Mangione mused about rebelling against “the deadly, greed fuelled health insurance cartel” and justified killing industry executives.

Mangione, the Ivy League-educated scion of a wealthy Maryland family, has pleaded not guilty to murder and other charges, and is expected to face trial next year.

He has pleaded not guilty in a separate federal case where prosecutors plan to seek the death penalty.

At Monday’s hearing, Mangione watched stoically as prosecutors played surveillance videos of Thompson’s killing and Mangione’s arrest five days later.

Mangione pressed a finger to his lips and a thumb to his chin as he watched footage of two police officers approaching him as he ate breakfast at a McDonald’s in Altoona, Pennsylvania, about 370km (230 miles) west of Manhattan.

He gripped a pen in his right hand, making a fist at times, as prosecutors played a 911 call from a McDonald’s manager relaying concerns from customers that Mangione looked like the suspect in Thompson’s killing.

“I have a customer here that some other customers are suspicious of, who looks like the CEO shooter, and they’re really upset, and they’re coming to me,” the employee was heard saying in a recording of the call played in court for the first time.

Mangione could face life in prison if convicted of murder in the second degree, which is defined as an intentional killing. He also faces seven counts of criminal possession of a weapon and one count of possessing a false identification.

Judge Carro dismissed two terrorism counts against Mangione in September, finding prosecutors had not presented enough evidence that Mangione intended to intimidate health insurance workers or influence government policy.

Several supporters of Mangione appeared outside the court before the hearing, including one dressed as the villain from the video game Super Mario Bros, bearing a sign that said, “When patients die, profits rise”, and a woman with a “Free Luigi” sash.

Advertisement Trial dates have not been set in either the state or federal cases.

Based on reporting by Al Jazeera.