Key Facts

• Federal prosecutors are seeking the death penalty for Luigi Mangione, suspected in the killing of UnitedHealthcare CEO Brian Thompson.
• Prosecutors argue that Mangione killed Thompson as a part of an ideological message against the health insurance sector.
• The death penalty proposal was filed ahead of Mangione's plea hearing for four federal charges.
• Mangione has been arrested for the crime in Pennsylvania following a nationwide search.
• Mangione has already pleaded not guilty to state charges and is waiting for trial in a New York prison.
• In addition to state charges, federal prosecutors have separately charged Mangione with using a firearm to commit murder and interstate stalking resulting in death.
• Brian Thompson was shot dead outside a hotel on December 4, where an investors' meeting of his company was being conducted.
• Mangione was caught five days after the incident at a McDonald's in Altoona, Pennsylvania.