A 26-year-old man was arrested Monday over the targeted killing of a health insurance executive on the streets of New York, with investigators charging him with possession of fake IDs and a gun.

Investigators continued to interrogate Luigi Mangione in connection with last week's brazen murder, which triggered a nationwide manhunt and global headlines.

He arrived at a Pennsylvania court wearing a dark sweatshirt on Monday evening and was led inside by Altoona police flanked by NYPD detectives where he was arraigned, broadcasters showed.

Mangione is next due to appear in court on December 23.

Pennsylvania Governor Josh Shapiro said that murder charges in New York state would follow, telling a media briefing "we do not kill people in cold blood to resolve policy differences or express a viewpoint."

Police have not confirmed reports the words "delay" and "deny" – language used by insurers to reject claims – were written on casings found at the scene, hinting at a possible political motive for the crime.

Mangione was apprehended by officers following a tip from staff at an Altoona McDonald's branch, where he was found wearing a mask and a beanie while using a laptop, and gave officers a fake ID, charging documents show.

They then searched him and found what police called a "ghost gun" capable of firing 9MM rounds and equipped with a suppressor that could have been made on a 3D printer.

When officers asked if he had been to New York recently, Mangione "became quiet and started to shake," according to the criminal complaint.

One of the fake IDs found was that used to check in to a Manhattan hostel ahead of the attack, discovered alongside a document that spoke to Mangione's "motivation and mindset", New York police said.

Mangione was born and raised in Maryland, studied at the Ivy League University of Pennsylvania, and had been living in Hawaii ahead of the killing.

"He matches the description of the identification we've been looking for. He's also in possession of several items that we believe will connect him to this incident," said New York mayor Eric Adams.

Police told reporters that Mangione possessed material that suggested he had "ill-will towards corporate America". (AFP)