A 20-year-old man has been shot dead while playing Pokémon Go at a tourist spot on San Francisco’s waterfront. US park police said Calvin Riley was shot on Saturday night by an unknown assailant at Aquatic Park near Ghirardelli Square. “From what we know there was no confrontation. There was nothing said back and forth. It was just senseless, just came up and shot in the back and ran away for nothing,” a family friend, John Kirby, said. He said Riley and a friend were playing Pokémon Go when Riley was shot.