The person questioned in Pennsylvania in connection with the shooting of United Healthcare CEO Brian Thompson has been identified as Luigi Mangione, according to six law enforcement officials with knowledge of the investigation.

Mangione, 26, was arrested by police in Altoona, Pennsylvania, on firearms charges but was not charged in Thompson’s killing, officials said Monday.

Investigators are looking into whether Mangione had recently traveled by bus from Philadelphia, about 240 miles away, to Altoona, a senior law enforcement official said.

According to two senior police officials, Mangione was found at a McDonald’s restaurant with several fake IDs, including one with the name “Marc Rosario.” He was recognized by an employee who called local police, officials said at a news conference.

Police said last week that the suspected shooter arrived in New York City by bus in late November and stayed in a Manhattan hostel.

The man who checked into the hostel also used a fake New Jersey ID with the same name, “Marc Rosario,” according to three sources familiar with the investigation.

Thompson, 50, was shot and killed outside New York’s Hilton Midtown on the morning of Dec. 4 as he was on his way to speak at an investor conference.

Police said the gunman appeared to have been waiting for his intended target in what New York Police Commissioner Jessica Tisch called a “premeditated, pre-planned targeted attack.”

The masked gunman approached Thompson from behind and shot him at least once in the back and once in the right calf. The words “deny,” “delay,” and “depose” were written on the bullet casings found at the scene.

According to police, the shooter fled on foot and then on a bicycle into Central Park.

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