Luigi Mangione pleaded guilty Friday in federal court to stalking charges tied to the 2024 broad daylight killing of UnitedHealthcare CEO Brian Thompson in New York City.

Why it matters: Mangione's lawyers are now using Friday's federal plea to request that all but one separate state charge be dismissed.

  • They claimed double jeopardy, a legal protection that prevents a person from being charged twice for the same offense.

Driving the news: Mangione's trial over the two federal charges — interstate stalking resulting in death and stalking through use of interstate facilities resulting in death — was scheduled for January 2027. He had previously pleaded not guilty.

  • During Friday's hearing, Judge Margaret Garnett told Mangione he will still be required to serve up to 85% of his sentence for the federal charges.

"I shot Mr. Thompson," Mangione said during Friday's hearing, adding, "I knew what I was doing was illegal," per multiple reports.

  • He described traveling to Manhattan ahead of the shooting, and seeking information about the conference Thompson was attending by posing as an investor. Mangione also described creating a gun with a 3D printer and attaching a silencer to it.
  • Garnett accepted his guilty plea and scheduled Mangione's sentencing for December 18.

Catch up quick: Mangione is accused of fatally shooting Thompson in midtown Manhattan in December 2024. The attack, which occurred outside a large hotel, sparked intense media coverage and a days-long manhunt for a suspect.

  • Mangione was ultimately arrested at a McDonald's in Altoona, Pennsylvania, where he was charged with five counts unrelated to Thompson's killing.
  • Mangione became something of an idolized figure online, as people frustrated with the state of U.S. health care and the insurance industry vented and praised him for taking action.
  • Mangione's manifesto expressed his disdain for the health insurance industry, though he never appeared to be a UnitedHealthcare client.

Zoom out: Mangione is still facing a trial in New York state court next month, where he will face some of the most serious charges levied against him.

  • Mangione has pleaded not guilty to all eight charges in New York; if convicted, he could face a life sentence.
  • There is no death penalty in New York.

Go deeper: America obsesses over Luigi Mangione's digital footprint

Editor's note: This story has been updated with additional information throughout.