Prosecutors say Luigi Mangione, accused of killing the CEO of UnitedHealthcare on a Manhattan sidewalk, has inspired others to embrace violence over reasoned debate.

As evidence of Mangione's growing influence, prosecutors cited the last month's deadly mass shooting at the National Football League headquarters.

The prosecution outlined the threat in a filing late Wednesday on a procedural matter in federal court in Manhattan, where they plan to try to convince a jury that Mangione deserves death. No federal trial date has been set.

Mangione, who pleaded not guilty to state and federal charges, was arrested five days after the Dec. 4 killing of CEO Brian Thompson. He is being held without bail in a federal jail in Brooklyn.

U.S. Attorney General Pam Bondi announced in April that she was directing federal prosecutors to seek the death penalty for "an act of political violence" and a "premeditated, cold-blooded assassination that shocked America."

In their filing Wednesday, prosecutors wrote that Mangione poses a continuing danger in part because he seeks to influence others.

"Simply put, the defendant hoped to normalize the use of violence to achieve ideological or political objectives," they said. "Since the murder, certain quarters of the public ? who openly identify as acolytes of the defendant ? have increasingly begun to view violence as an acceptable, or even necessary, substitute for reasoned political disagreement."

Prosecutors said Mangione has "openly cultivated supporters" by setting up a website and directly addressing them. They said Mangione also has catalogued all of the supportive letters he has received on his website.

In a footnote, prosecutors referenced the gunman who went into an office building not far from where Thompson was shot in midtown Manhattan, then killed four people including an off-duty police officer, a financial services firm executive and a security guard, and wounded others, including an NFL employee.

Mangione is accused of leaving behind evidence showing disdain for the insurance industry. Similarly, the NFL headquarters gunman identified as Shane Tamura left behind a handwritten note blaming the league and football for causing chronic traumatic encephalopathy, known at CTE, prosecutors noted.

Tamura, who took his own life, accused the league of hiding the dangers of brain injuries linked to contact sports.

Law enforcement sources say investigators recovered a three-page rambling note from Tamura's wallet in which he referenced the brain disease CTE. According to the sources, the note said he wanted to have his brain donated to science so it could studied for the disease.

"He did have a note on him. The note alluded to that he felt he had CTE, a known brain injury for those who participate in contact sports. He appeared to have blamed the NFL for his injury," New York Mayor Eric Adams said on "CBS Mornings."

CTE, or chronic traumatic encephalopathy, is caused by repeated trauma to the head. It came into the spotlight in recent years as more high-profile cases have been confirmed.

"Almost immediately, members of the public sympathetic to the defendant (Mangione) touted Tamura's actions as a laudable continuation of the defendant's philosophy," prosecutors said.(CBS News)

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