Jesus Solis, a man in his 20s, was fatally shot during an altercation shortly before 4 p.m. Sunday in the 1200 block of Treat Street.
Police are searching for a second suspect, identified as Dylan Lemalie, 20, of San Francisco.
A $5,000,000 murder warrant has been issued for Lemalie's arrest. Police said he should be considered armed and dangerous and that nobody should attempt to detain him.
Anyone with information on Lemalie's whereabouts is asked to notify police immediately at (415) 553-1145 or the anonymous tip line at (415) 575-4444.