Federal prosecutors allege Luigi Mangione, the accused killer of United Healthcare CEO Brian Thompson, has become an inspiration for political violence, including last month's deadly NFL headquarters shooting, while cultivating supporters from his Brooklyn prison cell.
The 27-year-old defendant faced harsh arguments in an August 27, 2025 court filing, as prosecutors debated that: "Respondent hoped to normalize the use of violence to achieve ideological or political objectives and has successfully influenced others through a website maintained from prison.”
Prosecutors cited the July 28 NFL headquarters attack by shooter Shane Tamura, who killed four people before taking his own life, as evidence of Mangione's influence.
Investigators connect his influence with recent crimes mastermind as they earlier found a red notebook in which Mangione detailed his plans against what he called the deadly, greed fueled health insurance cartel.
State attorneys filing notes supporters openly identify as Mangione's admirers and increasingly view violence as an acceptable, or even necessary, substitute for reasoned political disagreement.
Brian Thompson claimed the assassin awaits trial for the December 4, 2024 ambush killing of the CEO on a New York City street.
Mangione has pleaded not guilty to federal charges including murder, stalking, and firearms offenses related to the alleged use of a silencer.
The high-profile murder case has drawn extraordinary public response, with Mangione's legal defense fund surpassing $1 million in donations from more than 28,000 contributors, many expressing anger toward America's for-profit healthcare system.