Docs Reveal New Details of What Luigi Mangione Was Allegedly Thinking Before the Shooting of UnitedHealthcare CEO Brian Thompson

Luigi Mangione made several diary entries that reveal his thoughts prior to the December shooting of UnitedHealthcare CEO Brian Thompson, of which he is accused, New York City prosecutors claim in a new court filing.

The filing, submitted Wednesday, June 4 and obtained by PEOPLE, quotes the diary entries Mangione made in the months leading up to the shooting, which were found in a red notebook he was carrying at the time of his arrest in Altoona, Pa.

The alleged entries reveal that he seemingly considered what the public reception to such a high-profile crime would be.

“I finally feel confident about what I will do,” Mangione is alleged to have written in an August 2024 entry, according to prosecutors. “The details are coming together. And I don’t feel any doubt about whether it’s right/justified. I’m glad in a way that I’ve procrastinated [because] it allowed me to learn more about [UnitedHealthcare].”

Mangione also seemingly references a previous potential target, referred to as “KMD,” but wrote that it would have been an “unjustified catastrophe” and “would be perceived mostly as sick.”

“[KMD] would do nothing to spread awareness/improve people’s lives,” Mangione allegedly determined. “The target is insurance. It checks every box.”

In an entry dated in October 2024, a month-and-a-half before the shooting, Mangione allegedly wrote that the annual UnitedHealthcare investor conference — outside which Thompson would later be shot — “embodies everything wrong with our health system, and-most importantly-the message becomes self-evident.”

The alleged entry also directly mentioned the Unabomber, Ted Kaczynski, to whom Mangione has been compared. In it, Mangione acknowledged that a similar bombing likely would not be well-received by the public.

“For example, Ted K makes some good points on the future of humanity, but to make his point he indiscriminately mailbombs innocents,” Mangione allegedly wrote. “Normies characterize him as an insane serial killer, focus on the act/atrocities themselves and dismiss his ideas.”

Thompson was fatally shot outside the New York Hilton Midtown on the morning of Dec. 4, 2024 while on his way to the investor conference. The brazen killing in Manhattan and subsequent multi-state manhunt shocked the country and dominated headlines.

The night before the shooting, prosecutors allege that Mangione was walking adjacent to the hotel where the crime occurred while apparently talking on the phone. At the same time, Thompson walked past him in the opposite direction.

Since his arrest, Mangione has received a swell of support, despite the nature of the crime he’s charged with. His supporters have cited displeasure with the American health insurance industry.

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Mangione is charged with murder and terrorism in New York State, while federal prosecutors have charged him with murder and stalking. He has pleaded not guilty in both jurisdictions.

The Wednesday court filing was in response to a defense motion requesting that the state charges against Mangione be dismissed; his lawyers contend the dual charges constitute double jeopardy.

“If ever there were an open and shut case pointing to defendant’s guilty, this case is that case,” prosecutors wrote. “Simply put, one would be hard pressed to find a case with such overwhelming evidence of guilt as to the identity of the murderer and premeditated nature of the assassination.”