The Ivy League graduate arrested on suspicion of assassinating the CEO of UnitedHealthcare took issue with two of the prosecutor’s claims during his first court appearance on Monday night. Luigi Mangione, 26, was arrested earlier that day at a McDonald’s in Altoona, Penn., carrying a backpack with a black 3D-printed pistol, silencer, loaded Glock magazine and fake IDs, according to the criminal complaint. Prosecutors believe he gunned down Brian Thompson outside an investors meeting in New York