A Manhattan grand jury indicted Luigi Mangione on charges of first-degree murder, with prosecutors alleging he killed UnitedHealthcare CEO Brian Thompson "in furtherance of terrorism."
Prosecutors have also accused Mangione of second-degree murder, as well as a slew of counts related to the possession of an illegal "ghost gun" made from 3D-printed parts.
Following a five-day manhunt, Mangione was arrested last week at a restaurant in Altoona, Pennsylvania, on gun and false ID charges.
Police say he killed Thompson outside a midtown Manhattan hotel on December 4.
Prosecutors offered a detailed look Mangione's movements Tuesday. They say he stayed at an Upper West Side hostel for more than a week, using a fake New Jersey ID, before carrying out the killing.
According to prosecutors, two of the shell casings for the bullets that killed Thompson had the words "DENY" and "DEPOSE" written on them. The word "DELAY" was written on a bullet found at the scene.
An arrest warrant previously obtained by Business Insider indicated that Mangione would be charged with second-degree murder along with four other charges related to illegal weapon possession. The first-degree murder charge reflects a more severe charge.
If Mangione is convicted of the first-degree murder charge, he could spend the rest of his life in prison without parole. The charge, with the intent to commit terrorism, refers to a killing that is "intended to intimidate or coerce a civilian population" or "influence the policies of a unit of government by intimidation or coercion," according to the indictment.
"This type of premeditated, targeted gun violence cannot and will not be tolerated, and my office has been working day in and day out to bring the defendant to justice," Manhattan District Attorney Alvin Bragg said in a press release Tuesday.
Mangione has not yet entered a plea for any of the charges against him.
A Pennsylvania-based attorney for Mangione, a 26-year-old former Ivy League student, has contested Mangione's extradition to Manhattan.
Over the weekend, Mangione hired Karen Friedman Agnifilo, an experienced New York-based criminal defense attorney who is married to and shares a law firm with Marc Agnifilo. Marc Agnifilo is representing Sean "Diddy" Combs in his criminal sex-trafficking case.
In an interview with CNN prior to taking on Mangione as a client, Friedman Agnifilio said the evidence was "overwhelming" that Mangione killed Thompson.
"It looks like to me there might be a 'not guilty by reason of insanity' defense that they're going to be thinking about because the evidence is going to be so overwhelming that he did what he did," she said.
This story is breaking and will be updated.