Luigi Mangione pleaded not guilty Friday to stalking -- travel interstate commerce, stalking -- use of interstate facilities, murder through use of firearm and a firearm offense in the death of United Healthcare CEO Brian Thompson.

Luigi Mangione was arraigned Friday on federal charges in the December killing of UnitedHealthcare CEO Brian Thompson — a deliberate attack carried out to "amplify an ideological message" and stoke "broad-based resistance" to the health insurance industry, federal prosecutors said in a court filing.

Luigi Mangione pleaded not guilty Friday to federal murder and stalking charges, drawing a crowd of onlookers to the courthouse in New York City.