STOCKTON -- Sean and Kariann Riley tearfully pleaded with the public Thursday morning for answers in their son Calvin's homicide.
The Rileys say their son was well loved, talented baseball player for Delta College of San Joaquin, and missed every second of every day. The couple says Calvin's death has torn their family apart.
"You have no idea what you stole, what you took from this world," Kariann Riley said, delivering her message to her son's killer.
Calvin was shot in the back on August 6, 2016 at Aquatic Park in San Francisco. The 20-year-old was playing the popular Pokemon Go mobile game at the time.
Investigators with the United States Park Police say they do not have a motive, nor suspect information and are asking for the person or persons who did this to come forward.
"I would do anything to tell my kid I love him one more time," Sean Riley said.
The park police, city of San Francisco, and the Rileys are offering a combined $110,000 for information leading to the arrest and conviction of the murderer(s).
Investigators have also shared they are looking for a 2006-2009 dark colored Audi A3 wagon and a 2013 white 4-door Hyundai Sonata.
"It’s devastating and I think anybody who has lost someone in their life can't help but sympathize," Park Police Captain Jerry Marshall said. "So we’re hoping the individual who did it will come forward."