UnitedHealthcare CEO Latest Shooting: Person of Interest Luigi Mangione Under Arrest

Police are questioning Luigi Mangione, 26, of Altoona, Pa., as a person of interest in connection with the brazen killing of UnitedHealthcare CEO Brian Thompson in Midtown Manhattan last week, authorities say.

Mangione, of Maryland, was arrested by Altoona police on gun-related charges, according to authorities.

He was on a Greyhound bus traveling through Altoona Monday morning, sources said, when he got off and walked into a McDonald’s where a witness recognized him from police-released footage of the suspect.

Mangione was sitting and eating when a McDonald’s employee reported him, and “because of that, we believe we have a strong person of interest,” New York City Mayor Eric Adams said during the a press conference on Monday.

“He fits the description of the person we’re looking for,” Adams said.

Mangione had a ghost gun capable of firing a 9 mm round and a suppressor, police said.

Mangione was in possession of a handwritten document “that speaks to his motivation and his state of mind,” New York Police Commissioner Jessica Tisch said.

“It appears he had some ill will toward American businesses,” police said.

Authorities are examining his writings more closely to understand his motivations.

He also was in possession of a fake New Jersey driver’s license, similar to the one the suspect used to check into a New York inn before the shooting, Tisch said.

Tisch praised the “good old detective work” of the New York Police Department and the “power of the public” that led to the arrest.

Police said it appears Mangione acted alone and did not previously know his name.

Authorities said they were working to trace his movements from New York to Pennsylvania.

Meanwhile, new video obtained by ABC News shows the killer waiting for Thompson moments before the shooting.

The video shows other bystanders, then, when the masked gunman sees Thompson, he runs across the street and opens fire. The video, which has not been seen publicly before, appears to support the police account that the shooter targeted Thompson because he was loitering while others were strolling.

On Wednesday morning, the masked gunman shot Thompson at point-blank range outside the New York Hilton Midtown, where Thompson’s company was holding an investor conference. Tisch described the attack as “brazen” and “targeted.”

Right after the shooting, the suspect fled on a bicycle through Central Park toward the Upper West Side. He then took a taxi to the Port Authority bus facility on 178th Street and boarded a bus from New York, according to police.

Members of the NYPD dive team searched underwater in Central Park near the Bethesda Fountain on Sunday.

The suspect’s backpack – with a jacket and Monopoly money inside – was found near Central Park.

This is a developing story. Please check again for updates.

ABC News’ Bill Hutchinson, Jon Haworth, Ivan Pereira and David Brennan contributed to this report.