Luigi Mangione pleaded not guilty Friday to a federal murder charge in the killing of UnitedHealthcare CEO Brian Thompson. Prosecutors formally declared their intent to seek the death penalty

Luigi Mangione, the Maryland man accused of hunting down and killing a UnitedHealthcare CEO over what prosecutors said was "hostility toward the health insurance industry," pleaded not guilty at his Manhattan federal court arraignment on Friday to what could be death penalty charges.

Luigi Mangione, who is accused of shooting UnitedHealthcare CEO Brian Thompson dead in New York City, has entered a plea of not guilty as prosecutors say they are seeking the death penalty