But in a chaotic instant in May, three Border Patrol agents fatally shot Mr. Mattia as they came upon him in the desert, hitting him nine times, according to an autopsy. A Border Patrol report says he …But in a chaotic instant in May, three Border Patrol agents fatally shot Mr. Mattia as they came upon him in the desert, hitting him nine times, according to an autopsy. A Border Patrol report says he …