Summary (tl;dr)

A New York judge has ruled that a 3D-printed gun and a "manifesto" notebook can be used as evidence in the upcoming state murder trial of Luigi Mangione, who is accused of killing UnitedHealthcare CEO Brian Thompson.

Essential Background

Luigi Mangione is accused of fatally shooting Brian Thompson, the CEO of UnitedHealthcare, outside the New York Hilton Midtown in Midtown Manhattan, New York City, on December 4, 2024. Following a nationwide manhunt, Mangione was arrested five days later at a McDonald's in Altoona, Pennsylvania. Authorities found a 3D-printed pistol and a notebook in his backpack. Mangione was subsequently charged with both state and federal crimes, including first-degree murder in furtherance of terrorism (later dismissed) and second-degree murder in the state case, and interstate stalking resulting in death in the federal case. Federal prosecutors initially sought the death penalty, but a federal judge dismissed the death-eligible charges in January 2026.

The Full Story

Today, May 18, 2026, a New York state judge, Judge Gregory Carro, issued a key ruling on the admissibility of evidence for Luigi Mangione's state murder trial. The judge decided that the 3D-printed gun, which prosecutors allege is the murder weapon, and a notebook described as a "manifesto" expressing animosity towards the healthcare industry, can be presented as evidence. However, Judge Carro also ruled that other items found in Mangione's backpack during his initial arrest search—including a gun magazine, cellphone, passport, wallet, and computer chip—must be suppressed from the state trial, deeming that initial search at the McDonald's an "improper warrantless search" because the backpack was not within Mangione's immediate reach. The gun and notebook were permitted because they were recovered during a subsequent, lawful inventory search conducted at the police station. This ruling partially supports the prosecution's case ahead of the state trial, which is scheduled to begin on September 8, 2026, with a separate federal trial for stalking charges set to start in October.

Why It Matters

This ruling is significant for both the prosecution and defense in the high-profile murder trial of Luigi Mangione. For prosecutors, the ability to introduce the alleged murder weapon and Mangione's notebook is a major advantage, as these pieces of evidence are crucial for establishing motive and linking Mangione to Brian Thompson's killing. Conversely, the suppression of other items from the initial backpack search highlights ongoing legal debates regarding search and seizure laws and could impact how law enforcement conducts arrests and evidence collection. The case has garnered substantial public attention, partly due to Thompson's prominent position in the healthcare industry and the alleged motive related to criticisms of the American healthcare system, making the trial's outcome a matter of widespread interest.

Geographic Location

• New York Hilton Midtown, Midtown Manhattan, New York City, New York, United States (shooting of Brian Thompson)
• McDonald's, Altoona, Blair County, Pennsylvania, United States (Luigi Mangione's arrest)
• New York City, New York, United States (state court ruling on evidence)