A New York judge has ruled that a 3D-printed ghost gun and a notebook found in Luigi Mangione’s backpack will be admitted as evidence at his September murder trial, delivering prosecutors a significant win.
Mangione, 27, is accused of fatally shooting UnitedHealthcare CEO Brian Thompson on 4 December 2024 outside a Manhattan hotel. His arrest at a McDonald’s restaurant in Altoona, Pennsylvania days later produced a cache of items from his backpack that prosecutors and the defence have spent months fighting over in court.
Luigi Mangione trial: what the judge allowed
Judge Gregory Carro, presiding in Manhattan Criminal Court, ruled on 18 May 2026 that the 3D-printed firearm and the notebook would be placed before the jury.
The notebook contains writings in which Mangione expressed frustration with the United States health insurance industry; prosecutors intend to use it to establish motive.
The gun, described as a ghost gun with no traceable serial number, is expected to be presented as a possible murder weapon. Its admission is a significant development for prosecutors, who must prove not only that the shooting occurred but that Mangione carried out the act with intent.
What the judge threw out
The ruling was not a clean sweep for the state. Carro excluded several items retrieved from Mangione’s backpack before his formal arrest, including a loaded gun magazine, his cellphone, his passport, his wallet and a computer chip.
The judge found that officers had conducted “an improper warrantless search” at the McDonald’s.
Carro ruled that Mangione’s backpack was not in a “grabbable area” while he was being detained inside the restaurant, which is the legal threshold required to justify a search-incident-to-arrest.
Because the items were seized before that standard was met, they were obtained in violation of Mangione’s constitutional protections and cannot be placed before the jury.
When the Luigi Mangione trial is expected to begin
The state trial in Manhattan Criminal Court is currently scheduled to begin in September 2026. A separate federal case, in which Mangione faces charges that carry the possibility of a death sentence, is expected to follow in the autumn of 2026, though no date has been confirmed for those proceedings.
The two parallel prosecutions represent one of the more unusual features of the case. Legal observers have noted that evidentiary overlap between the state and federal trials will require prosecutors to manage the sequencing of each case carefully, particularly given the visibility the shooting attracted in the weeks following Thompson’s death.
The evidence hearing, which concluded on 18 May, was the last major procedural hurdle before the September state trial.
Jurors will now be shown the notebook and the 3D-printed gun, two items that prosecutors argue tell the clearest version of the story they intend to present in court.
