Federal prosecutors in Manhattan are advancing the death penalty case against Luigi Mangione for the murder of UnitedHealthcare CEO Brian Thompson outside a Manhattan hotel during an investor conference.Prosecutors oppose defense motions to dismiss charges and suppress key evidence collected at Mangione's arrest in Pennsylvania, including a 9 mm handgun and a notebook documenting intent to kill.Mangione has pleaded not guilty to federal and state murder charges, with the case drawing national attention amid debates on politicization and healthcare costs.