Mr. Mangione was formally charged Monday night with forgery, carrying a firearm without a license, falsifying records or identification, possession of instruments of crime and providing false police documents.
Pete Weeks, the district attorney for Blair County in Pennsylvania, said charges in the New York killing would be filed “tonight or tomorrow” or in the “near future.”
Mr. Mangione stopped cooperating after he was arrested, officials said.
Mr Mangione appeared in court on Monday in handcuffs, wearing jeans and a navy blue T-shirt. In court, he looked calm, periodically looking back at those present, including the media.
New York City investigators used one of the world’s largest digital surveillance systems, police dogs, drones and divers in a Central Park lake to search for evidence before the hunt spread to neighboring states.
But it appears a McDonald’s customer recognized the suspect from media coverage and alerted an employee, who tipped off authorities.
According to Pennsylvania authorities, officers were called to a report of a “suspicious male” who resembled the suspect in Thompson’s murder.
When officers arrived at the fast-food restaurant, Mr. Mangione showed them a fake New Jersey driver’s license in the name of Marco Rosario, court documents said.
He “became quiet and began to shake” when the officer asked if he had been to New York recently, the criminal complaint added.
When told he would be arrested if he lied about his name, he admitted he was Luigi Mangione, according to court documents.
When asked why he lied, he told officers that “I clearly shouldn’t have,” according to court documents.
A search of his backpack revealed a black 3D-printed gun, a silencer and a loaded magazine with six 9mm rounds.
Earlier in the day, New York Police Commissioner Jessica Tisch said the gun and silencer seized by investigators from the suspect “were both consistent with the weapon used in the murder.”
Once the charges are filed in New York, Mr. Mangione will have the option of refusing or contesting extradition.
If he refuses to do so, he will immediately become available to New York authorities. If he challenges it, the process can take 30 to 45 days.
A three-page handwritten document found in Mr. Mangione’s possession showed he had “ill will toward corporate America,” New York Detective Chief Joseph Kenney said.
Mr. Kenny said Mr. Mangione was born and raised in Maryland and has ties to San Francisco, California.
Authorities believe he may have attended the University of Pennsylvania, but his last known address was in Honolulu, Hawaii.
TrueCar, a website for car buyers, confirmed that he worked there but left in 2023.