Luigi Mangione pleaded not guilty to federal charges in the killing of UnitedHealthcare CEO Brian Thompson. Prosecutors declared their intent to seek the death penalty.

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.