Police have identified a 26-year-old Maryland man as a suspect in last week’s killing of UnitedHealthcare CEO Brian Thompson, who was shot in the back outside a New York Hilton hotel hours before a shareholder conference on Wednesday.

Luigi Nicholas Mangione was arrested Monday morning in Altoona, Pennsylvania, after witnesses spotted him and believed he was the suspect in a wanted poster. Police responded to the location for reports of a person matching the description of the man wanted for questioning in connection with Thompson’s killing. However, Altoona police said they initially took him into custody on unrelated charges.

Senior law enforcement sources told Fox News and Fox News Digital that he was carrying a “ghost gun” similar to the suspected murder weapon, a silencer and a fake ID when he was arrested. The Associated Press also reported that he had written critical of the health care industry.

SUSPECT IN HUNCH FOR BRIAN THOMPSON’S KILLER, UNITEDHEALTHCARE CEO, ARRESTED: LIVE UPDATES

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

Mangione graduated at the top of his class from the elite Gilman School, a private high school in Baltimore. The video of his graduation ceremony shows him giving the opening speech.

“He seemed like a smart kid, he always did the right thing, it seemed,” a former classmate told Fox News Digital on Monday. “Wasn’t crazy.”

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

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

“It’s not that he wasn’t outgoing or introverted,” he said. Nice boy, always had a smile on his face. I never really got the sense that he was socially awkward. That’s why I’m really surprised. I graduated in 2015; He completed his studies in 2016. It’s crazy how people can change ten, nine years later.”

NYPD believes the bomber, CEO of UnitedHealtHCARE, left New York City on a bus the morning of the shooting

This undated UnitedHealth Group photo shows Brian Thompson, CEO of UnitedHealthcare. (AP Photo/UnitedHealth Group via A)

In a statement, Gilman School called the attack a “horrible situation.”

“Luigi Mangione’s alleged involvement in this case is deeply disturbing news on top of an already terrible situation,” a spokesman told Fox News. “Our condolences go out to all those affected. Here on campus, our focus continues to be on supporting and educating our students.”

Mangione graduated from the University of Pennsylvania with bachelor’s and master’s degrees in engineering and was a member of the Eta Kappa Nu Honor Society in electrical and computer engineering.

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

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

A screenshot from surveillance footage released by the NYPD shows a suspect wanted in connection with the shooting of UnitedHealthcare CEO Brian Thompson on Wednesday, December 4, 2024, in Midtown Manhattan. (NYPD Crime Stoppers)

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New York City Mayor Eric Adams said at a news conference Monday that “it matches the description of the ID we are seeking” and that he is “in possession of several items that we believe may match him with this.” Connect incident.”

Fox News’ Greg Norman and Lillian LeCroy contributed to this report.