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.

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.

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, 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.

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.