SAN FRANCISCO—An unknown gunman shot and killed a 20-year-old man on Saturday, August 6 at the Aquatic Park near Ghirardelli Square, according to reports.

Calvin Riley was playing the popular cell phone game, Pokémon Go, at the tourist attraction with a friend. Riley and the friend noticed someone from a cliff overlooking the area, but it was dark and they were focused on their cell phones. The unknown assailant shot Riley from behind and took off. The suspect did not take any of Riley’s belonging or attempt to rob him. It is unclear as to whether Pokémon Go played a factor in this incident.

“From what we know, there was no confrontation,” said John Kirby to KGO-TV. “There was nothing said back and forth. It was just senseless, just came up and shot in the back and ran away for nothing.”

The National Park Service is investigating the incident. Authorities believe there are witnesses of the incident since the shooting occurred at the busy Fisherman’s Wharf area. National Park Service investigators are seeking tips on this case.

Riley graduated from high school in San Mateo and pitched for the baseball team at San Joaquin Delta College.