On the evening of April 25, 1958, a young Korean exchange student, a leader in student Christian affairs in the University of Pennsylvania, left his flat and went to the corner to post a letter to his parents in Pusan. Turning from the mailbox he stepped into the path of eleven leather-jacketed teenage boys. Without a word they attacked him, beating him with a blackjack, a lead pipe and with their shoes and fists. Later, when the police found him in the…