College student Calvin Riley, 20, was fatally shot Saturday night while playing Pokémon Go at Aquatic Park near Ghirardelli Square, a popular tourist area.
WATCH VIDEO: Man fatally shot while playing Pokemon Go in San Francisco
The problem with the investigation right now, is that there are no cameras at Aquatic Park.
Riley's family told ABC7 News they're inconsolable over the death of their son.
Riley was gunned down between 9:30 p.m. and 10 p.m. He was with a friend playing Pokémon Go when he was shot, but nothing was taken.
Investigators are struggling to find a motive.
A friend from Boston who witnessed the shooting was so devastated he flew home the next day.
Riley graduated from Serra High School in San Mateo a year ago, when he wrote thanks in his yearbook to his family for all of their sacrifices.
"It's really hard to wrap your brain around it. People are struggling to make sense of it and really trying to focus at this point on support for one another, for teachers, for friends, for colleagues, and certainly moving forward support for his wonderful mom and dad and his brother and sister," Serra High School Principal Barry Thornton said.
A GoFundMe account to help his family has already exceeded its $46,000 goal.
United States Park Police are leading the investigation and are soliciting social media posts from the public to try to find clues with the help of the San Francisco Police Department.
"I know the chief and homicide unit is investigating everything, they're looking at all of the possible video tapes that were in the area around the time to see whether we might be able to capture a suspect or identify somebody that might have been involved," San Francisco Mayor Ed Lee said.
"We don't have any cameras in the park here. Had it been on a city street, maybe a few blocks up that might've been a different story," National Park Police spokesperson Lynn Cullivan said.
The family says a memorial for Riley will be held on Thursday, August 11, with the viewing beginning at 6 p.m. and a vigil starting at 7 p.m. The funeral mass will be held on Friday, August 12 at 11 a.m. Both will be held at St. Gregory's Church in San Mateo and are open to the public.
Click here if you'd like to make a donation to help the family pay for funeral costs.
Anyone with information about the shooting is being asked to call the Police Department's anonymous tip line at (415) 575-4444 or text a tip to TIP411 with SFPD at the start of the message.