Who is Luigi Mangione, suspect in UnitedHealthcare CEO murder?

ALTOONA, Pa. – Police have identified a 26-year-old Maryland man as the suspect in last week's assassination of UnitedHealthcare CEO Brian Thompson, who was shot from behind outside a New York City Hilton hotel hours before a shareholder conference Wednesday.

Luigi Nicholas Mangione was arrested in Altoona, Pennsylvania, Monday morning after a McDonald's customer and employee spotted him and thought he matched the suspect on a wanted poster. Police responded to the location for reports of a person matching the description of the man wanted for questioning in Thompson's murder, but Altoona police said they initially took him into custody on unrelated charges.

When officers approached, they immediately recognized him, even though he was wearing a medical mask, according to court documents. However, he allegedly handed over a fake ID and gave a phony name. When police asked if he'd recently been to New York, Mangione allegedly "became quiet and started to shake."

High-level law enforcement sources told Fox News and Fox News Digital that he had a "ghost gun" similar to the suspected murder weapon, a suppressor and a fake ID in his possession when taken into custody. The Associated Press also reported he had writings critical of the healthcare industry.

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Luigi Mangione pictured in a police holding cell in Altoona, Pennsylvania. (Obtained by Fox News Digital)

Mangione graduated from the elite Gilman School, a private high school in Baltimore, at the top of his class. Video of his graduation ceremony shows he delivered the commencement speech, where he thanked his parents and his classmates' parents for making the investment.

"He seemed like a smart kid, he was always doing the right thing, it seemed like," a former classmate told Fox News Digital Monday. "Wasn’t crazy."

He said the news came as a shock when he heard of the arrest. 

Read the Pennsylvania arrest warrant:

"It's not like he wasn’t outgoing, or introverted," he said. Nice kid, always had a smile on his face. Never really got the vibes of him being socially awkward. So that’s why I’m really surprised. I graduated in 2015; he graduated in 2016, It’s crazy how 10, nine years later, how people can change."

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Luigi Mangione pictured in a Facebook photo. Mangione was taken into custody in Altoona, Pennsylvania, Monday morning in connection with the ambush murder of UnitedHealthcare CEO Brian Thompson in New York City. (Luigi Mangione/Facebook)

In a statement, the Gilman School called the assassination an "awful situation."

"Luigi Mangione’s suspected involvement in this case is deeply distressing news on top of an already awful situation," a spokesperson told Fox News. "Our hearts go out to everyone affected. Here on campus, our focus will remain on caring for and educating our students."

Mangione went on to graduate from the University of Pennsylvania with bachelor and master's degrees in engineering and was part of the Eta Kappa Nu Honor Society for Electrical and Computer Engineering.

WATCH: Luigi Mangione delivers 2016 valedictorian speech

Video

Mangione was active on social media, with accounts on X, Facebook and Instagram. Posts discussed a range of interests, including artificial intelligence and social commentary.

His criminal record includes a December 2023 misdemeanor case in Honolulu, Hawaii, for trespassing at the Nuuanu Pali Lookout.

Luigi Mangione poses with a McDonald's meal in a Facebook photograph posted on Aug. 24, 2019. He was arrested at a McDonald's in Altoona, Pennsylvania, Monday in connection with the shooting death of UnitedHealthcare CEO Brian Thompson. (Luigi Mangione/Facebook)

He was a periodic poster on Goodreads, the literature-focused social media site, where he wrote a review for a book by the Unabomber Ted Kaczysnki. 

"It's easy to quickly and thoughtless write this off as the manifesto of a lunatic, in order to avoid facing some of the uncomfortable problems it identifies," he wrote. "But it's simply impossible to ignore how prescient many of his predictions about modern society turned out."

A screenshot from surveillance footage released by the NYPD shows an alleged person of interest wanted in connection of the shooting death of UnitedHealthcare CEO Brian Thompson in Midtown Manhattan on Wednesday, December 4, 2024. (NYPD Crime Stoppers?)

Writing about Kaczynski's "Industrial Society and Its Future," he quoted another online "take that [he] found interesting."

"When all other forms of communication fail, violence is necessary to survive," he wrote. "You may not like his methods, but to see things from his perspective, it's not terrorism, it's war and revolution."

NYPD Chief of Detectives Joseph Kenny told Fox News over the weekend that it was too soon to allege a motive but acknowledged that the suspect did leave potential clues behind.

"We're not going to commit to a motive right now, but, you know, obviously when you look at the writing, you look at the victim's employment, you know, it could possibly be a disgruntled employee or a disgruntled client, but we're not we're not ruling that out, but we certainly not committing to it at this time," Kenny said.

This undated photo provided by UnitedHealth Group shows UnitedHealthcare chief executive officer Brian Thompson. (AP Photo/UnitedHealth Group via A)

At the scene, police found bullet casings with handwritten words on them, "depose," "deny" and "defend," drawing comparisons to the book "Delay, Deny, Defend: Why Insurance Companies Don't Pay Claims and What You Can Do About It" – speculation swirled that the slaying may have grown out of resentment for a denied claim.

The book was not found on Mangione's Goodreads account when accessed before it was set to private Monday.

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New York City Mayor Eric Adams said at a press conference Monday that "He matches the description of the identification we've been looking for" and that he is "in possession of several items that we believe will connect him to this incident." 

Mangione was expected to be transferred to New York as early as Tuesday. He was initially arrested on fake ID and unlawful possession of a firearm charges.

Fox News' Greg Norman, Brooke Curto, Julia Bonavita and Lillian LeCroy contributed to this report.