Luigi Mangione shouts as he is led into courthouse where he contests extradition to N.Y.

ALTOONA, Pa. -

The man accused of killing UnitedHealthcare’s CEO struggled with deputies and shouted while being led into court Tuesday as new details emerged about his possible motivation behind the ambush.

In his first public words since a five-day search ended with his arrest at a McDonald's in Pennsylvania, Luigi Nicholas Mangione emerged from a patrol car shouting about an “insult to the intelligence of the American people” while deputies pushed him inside a courthouse.

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The 26-year-old Ivy League graduate from a prominent Maryland real estate family is fighting attempts to extradite him to New York so that he can face a murder charge in the Manhattan killing of Brian Thompson, who led the United States’ largest medical insurance company.

A law enforcement bulletin obtained by The Associated Press said that at the time of his arrest, Mangione was carrying a handwritten document expressing anger with what he called “parasitic” health insurance companies and a disdain for corporate greed and power.

He wrote that the U.S. has the most expensive health care system in the world and that profits of major corporations continue to rise while “our life expectancy” does not, according to the bulletin.

In social media posts, Mangione called “Unabomber” Ted Kaczynski — who carried out a series of bombings while railing against modern society and technology — a “political revolutionary,” according to the police bulletin.

This combo image released by Pennsylvania State Police shows Luigi Mangione at a McDonald's in Altoona, Pa., Monday, Dec. 9, 2024. (Pennsylvania State Police via AP)

Mangione remained jailed in Pennsylvania, where he was initially charged with possession of an unlicensed firearm, forgery and providing false identification to police.

Manhattan prosecutors were beginning to take steps to bring Mangione to New York, but at a brief hearing Tuesday, defense lawyer Thomas Dickey said his client will not waive extradition and instead wants a hearing on the issue. Mangione was denied bail after prosecutors said he was too dangerous to be released.

He mostly stared straight ahead at the hearing, occasionally looking at papers, rocking in his chair or looking back at the gallery. At one point, he began to speak to respond to the court discussion but was quieted by his lawyer.

“You can’t rush to judgment in this case or any case,” Dickey said afterward. “He’s presumed innocent. Let’s not forget that.”

Mangione was arrested in Altoona, Pennsylvania, about 230 miles (about 370 kilometres) west of New York City, after a McDonald’s customer recognized him and notified an employee, authorities said.

Images of Mangione released Tuesday by Pennsylvania State Police showed him pulling down his mask in the corner of the McDonald's while holding what appeared to be hash browns and wearing a winter jacket and beanie. In another photo from a holding cell, he stood unsmiling with rumpled hair.

Fake ID found on suspected CEO shooter that NYPD believes was used in NYC. (Obtained by CNN)

New York police officials have said Mangione was carrying a gun like the one used to kill Thompson and the same fake ID the shooter had used to check into a New York hostel, along with a passport and other fraudulent IDs.

A law enforcement official who wasn’t authorized to discuss the investigation publicly and spoke with The Associated Press on condition of anonymity said a three-page, handwritten document found with Mangione included a line in which he claimed to have acted alone.

This booking photo provided by Pennsylvania Department of Corrections on Tuesday, Dec. 10, 2024, shows shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (Pennsylvania Department of Corrections via AP)

“To the Feds, I’ll keep this short, because I do respect what you do for our country. To save you a lengthy investigation, I state plainly that I wasn’t working with anyone,” the document said, according to the official.

It also said, “I do apologize for any strife or traumas but it had to be done. Frankly, these parasites simply had it coming.”

Thompson, 50, was killed last Wednesday as he walked alone to a Manhattan hotel for an investor conference. From surveillance video, New York investigators determined the shooter quickly fled the city, likely by bus.

Mangione was born into a life of country clubs and privilege. His grandfather was a self-made real estate developer and philanthropist.

This booking photo released Monday, Dec. 9, 2024, by the Pennsylvania Department of Corrections shows Luigi Mangione, a suspect in the fatal shooting of UnitedHealthcare CEO Brian Thompson. (Pennsylvania Department of Corrections via AP)

Valedictorian at his elite Baltimore prep school, he went on to earn undergraduate and graduate degrees in computer science in 2020 from the University of Pennsylvania, a spokesperson said.

“Our family is shocked and devastated by Luigi’s arrest,” Mangione’s family said in a statement posted on social media late Monday by his cousin, Maryland Del. Nino Mangione. “We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved.”

From January to June 2022, Luigi Mangione lived at Surfbreak, a “co-living” space at the edge of touristy Waikiki in Honolulu.

Luigi Mangione is seen in a photo posted in 2019. (Obtained by CNN)

Like other residents of the shared penthouse catering to remote workers, Mangione underwent a background check, said Josiah Ryan, a spokesperson for owner and founder R.J. Martin.

“Luigi was just widely considered to be a great guy. There were no complaints,” Ryan said. "There was no sign that might point to these alleged crimes they’re saying he committed.”

At Surfbreak, Martin learned Mangione had severe back pain from childhood that interfered with many aspects of his life, from surfing to romance, Ryan said.

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Mangione left Surfbreak to get surgery on the mainland, Ryan said, then later returned to Honolulu and rented an apartment.

Martin stopped hearing from Mangione six months to a year ago.

Scolforo reported from Altoona and Hollidaysburg, Pennsylvania. Contributing were Associated Press writers Cedar Attanasio and Jennifer Peltz in New York; Michael Rubinkam and Maryclaire Dale in Pennsylvania; Lea Skene in Baltimore; Jennifer Sinco Kelleher in Honolulu and John Seewer in Toledo, Ohio.