Article continues below advertisementLuigi Mangione appeared cool as a cucumber as he entered a Manhattan courtroom with a pump of his fist on Monday, December 8. Mangione - who's been receiving love letters in jail - attended an evidence suppression hearing ahead of his trial for allegedly murdering UnitedHealthcare CEO Brian Thompson last December. The assumed killer, 27, looked indifferent as bodycam footage from the day of his arrest showed officers discovering ammunition stored in a pair of wet underwear in his backpack.