Luigi Mangione has been charged with murder of UnitedHealthcare ...

Luigi Mangione faces a second-degree murder charge in New York in connection with the death of UnitedHealthcare CEO Brian Thompson, according to an online court docket filed Monday.

The 26-year-old was also charged with possession of a loaded firearm, possession of a forged instrument and criminal possession of a weapon, according to the docket.

The forged instrument is the fake NJ driver’s license that he allegedly used to check into the hostel on the Upper West Side.

Mangione remains in the custody of the Pennsylvania Department of Corrections pending his extradition to New York.

The Manhattan District Attorney’s office confirmed the charges. Court records explaining them will not be unsealed until Mangione appears in court in New York at a later date.

The New York charges came hours after Mangione was arrested in Altoona, Pennsylvania.

He had been identified by an employee at a McDonald's, based on photographs circulated by the police of their person of interest in what was called a "brazen, targeted" attack in Midtown Manhattan on Dec. 4.

The Pennsylvania Department of Corrections released Mangione's mugshot on Monday evening.

He had been charged earlier in the day with five crimes, including carrying a gun without a license, forgery, falsely identifying himself to authorities and possessing "instruments of crime," according to the criminal complaint in Pennsylvania.

The charging document alleged that Mangione lied about his identity to police and carried the ghost gun without a license.

The gun and suppressor were "consistent with the weapon used in the murder," NYPD Commissioner Jessica Tisch said following Mangione's arrest on Monday.

During the search of Mangione's backpack upon his arrest, officers allegedly found a black 3-D printed pistol and a black silencer, which was also 3-D printed, according to the criminal complaint.

"The pistol had one loaded Glock magazine with six nine-millimeter full metal jack rounds. There was also one loose nine-millimeter hollow point round," the complaint alleges.

NYPD Chief of Detective Joe Kenny described the weapon allegedly found on Mangione as a "ghost gun," meaning it had no serial number and was untraceable.

Also recovered from Mangione at the time of his arrest were several handwritten pages.

Kenny said that the document contained writing that expressed "some ill will toward corporate America."

The writings mention UnitedHealthcare by name, law enforcement sources told ABC News.

The sources described the handwriting as sloppy and included these quotes: “These parasites had it coming” and “I do apologize for any strife and trauma, but it had to be done."

Police are now looking at Mangione’s travel at various points across the United States and out of the county within the past year, the sources said.

This story has been updated.