The man accused of killing UnitedHealthcare CEO Brian Thompson now faces federal charges, including murder and stalking, alongside state murder and terrorism charges previously filed in New York. Luigi Mangione, 26, was formally charged in a Manhattan federal court on Thursday, following his extradition from Pennsylvania.

Federal prosecutors in Manhattan charged Mangione with murder using a firearm, two counts of stalking, and possession of an illegal gun silencer. The criminal complaint alleges Mangione meticulously planned the December 4 shooting, driven by contempt for the health insurance industry and its executives. A notebook found in his possession included detailed notes about his intent to target Thompson at a company conference, referring to the event as a “true windfall” and claiming the act would send a self-evident message.

Mangione also carried a letter addressed to federal authorities, in which he claimed to have acted alone, describing the attack as requiring "elementary social engineering, basic CAD, and a lot of patience."

Mangione was arrested in Altoona, Pennsylvania, on December 9, following a five-day manhunt. Police found him with a self-assembled 9mm handgun, a homemade silencer, and multiple fake identification documents. Surveillance footage linked him to a Manhattan hostel where he stayed before the shooting. On Thursday, Mangione waived his right to an extradition hearing, clearing the way for his transfer to New York.

Dressed in a blue sweater and beige slacks, Mangione appeared before U.S. Magistrate Judge Katharine Parker in Manhattan later that day. He spoke briefly to confirm his understanding of the federal charges and was ordered to remain in custody without bail.

Mangione’s defense attorney, Karen Friedman Agnifilo, criticized the addition of federal charges, calling them "highly unusual" and raising concerns about potential double jeopardy. While New York does not have the death penalty, federal prosecutors could pursue it for the federal murder charge. The silencer charge carries a minimum sentence of 30 years in prison.

Federal prosecutors argue that Mangione’s use of interstate travel, a mobile phone, and the internet to plan and execute the crime provides federal jurisdiction. The Manhattan District Attorney’s Office has separately charged Mangione with first-degree murder and murder as an act of terrorism under New York law.

Thompson’s killing has sparked outrage, with Manhattan District Attorney Alvin Bragg calling it an act of terrorism designed to intimidate civilians and influence government policies. At the same time, Mangione has gained a small but vocal following among critics of the U.S. health insurance system. Supporters gathered outside the Blair County Courthouse in Pennsylvania during his hearing, holding signs condemning the health insurance industry.

Thompson, 50, was the CEO of UnitedHealthcare, the largest health insurer in the U.S. His killing has drawn attention to public frustration with healthcare costs and insurance practices, with some expressing empathy for Mangione’s alleged motives while condemning his actions.

Mangione has yet to enter a plea in either the federal or state cases. His next court appearance will focus on the federal charges, while the Pennsylvania proceedings have been paused until the New York cases conclude.