New York prosecutors charged Luigi Mangione with murder late Monday night in the death of UnitedHealthcare CEO Brian Thompson.
In addition to murder, Mangione is charged with firearms and forgery offenses in New York.
Mangione is currently being held without bail in a state prison in Huntingdon County, Pennsylvania.
The 26-year-old was arrested on Monday at a McDonald's in Altoona after police received a tip about a man matching the description of the individual wanted in connection to the murder of Thompson.
A police report says Mangione initially presented officers with a fake ID. It had the same name police said Mangione used at a hostel in New York prior to allegedly killing Thompson, police said.
When confronted about the fake ID, police said Mangione told them his real name. He was then placed under arrest.
"Officers recovered a firearm on his person as well as a suppressor, both consistent with the murder," said NYPD Commissioner Jessica Tisch. "They also recovered clothing, including a mask consistent with those worn by our wanted individual."
Police say the pistol they found in Mangione's backpack had a metal slide and barrel and a plastic handle. They also found a plastic suppressor, six 9mm bullets in a Glock magazine and one loose round.
Authorities believe the firearm was a "ghost gun" that was likely made with a 3D printer.
RELATED STORY | 'Depose,' 'Deny,' 'Defend' reportedly written on shell casings in slaying of UnitedHealthcare CEO
Mangione is charged with firearms and forgery offenses in Pennsylvania. It's unclear when he will be extradited to face the more serious murder charge in New York.
While police haven't a definitive motive, writings recovered during Mangione's arrest could shed light on his mindset. NYPD Chief of Detectives Joseph Kenny said the materials suggested Mangione harbored "ill will toward corporate America."
Mangione's family, which is well-known in Maryland, where he is from, released a statement Monday night, saying they are "shocked" and "saddened" by the arrest.
"We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved. We are devastated by this news," the statement says.
RELATED STORY | Suspect in health care CEO's murder attended Ivy League school