SAN MATEO, Calif. (KGO) -- Calvin Riley was shot and killed six months ago at San Francisco's Aquatic Park.
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The gunman still hasn't been found.
Friends and family gathered Thursday night to remember Calvin and make a major announcement about the criminal investigation.
Six months after someone shot Riley in the back his former baseball team, friends, and family held a vigil at San Mateo's Central Park.
"It's a nightmare every day," said Riley's father Sean. "It's a nightmare."
He announced a $50,000 reward for information leading to an arrest. He wants the shooter to hear his pain. "You ripped my heart out of my chest," said Sean. "You took my best friend, my everything. You took everything from me on that night."
"That night" was Aug. 6. Calvin was playing "Pokemon Go" on his cellphone with a friend near Ghiradelli Square when he was shot.
"Our end goal is to put handcuffs on the perpetrator of this heinous event," said Lt. Timothy Hodge of the United States Park Police, who showed up at Thursday's vigil.
They're pursuing leads but need more information. "We're hoping that with the announcement that Sean made, offering the reward, that would shake some other people to do the right thing," said Hodge. "To speak on what occurred."
Riley's friends are pleading for the same. "Please confess," said Thomas McCarthy. "You know what you did was wrong. You took someone away that was way too young."
RELATED: Man fatally shot while playing Pokemon Go in San Francisco
Police are looking for a white Hyundai Sonata and dark-colored vehicle seen near the park the night of the shooting.
Father offers $50K reward after son killed playing Pokemon Go in San Francisco
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