Luigi Mangione spent his first full day in a federal facility known as “hell on earth.” The 26-year-old accused assassin is being held in isolation in New York’s Metropolitan Detention Center. It’s notorious for appalling conditions and rampant inmate violence. After processing, Mangione will be moved to a special housing unit on the 18th floor where he will share common space with Sean “Diddy” Combs, who is awaiting trial for sex trafficking.