A man is being held for questioning in Altoona, Pennsylvania, in connection with the murder of UnitedHealthcare CEO Brian Thompson. The New York Times Reports.

A law enforcement source said the suspect was identified thanks to a tip from a “senior patron” who spotted him at a McDonald’s in Altoona. The suspect reportedly had a gun, a silencer and fake IDs similar to those the killer was believed to have used in New York City.

When authorities approached him at a McDonald’s, the suspect reportedly showed police the same fake New Jersey ID that the shooter was believed to have used when he checked into a Manhattan hostel on November 24. Police also said he carried a handwritten manifesto criticizing healthcare companies and the way they put profits over patient care.

Authorities said the suspect arrived in Altoona on a Greyhound bus. They search the passenger manifest to see if any names match those on the suspect’s other fake IDs.

The detained suspect has not been arrested or charged in connection with the shooting, although he was reportedly arrested on local charges (possibly related to allegedly presenting a fake ID). If the suspect is believed to be Thompson’s killer, he would have to be extradited to New York to face charges. His name has not yet been released.

The questioning is the most significant development in the manhunt for the gunman since Thompson was killed outside New York’s Hilton Midtown on the morning of Dec. 4. Authorities described the killing as a “pre-planned, targeted attack” at the scene. As part of the crime, they recovered several bullet casings engraved with the words “deny,” “defend” and “depose” – a possible reference to terms used by Health insurance companies are used to avoid paying claims.

After the attack, authorities assumed that the shooter fled the scene first on foot and then on a bicycle. He is believed to have quickly left New York City by bus, with surveillance cameras catching him entering but not leaving the Port Authority Bus Terminal. Police officers also recovered a backpack in Central Park reportedly filled with Monopoly money that they believe belonged to the shooter.

In addition to tracking his movements, police also shared a handful of photos of the suspect selected from surveillance footage. These included images of the shooter in a Starbucks and in a taxi, although his face was obscured in both images. Pictures of the gunman without a face mask were taken at the hostel where he was reportedly staying.