It happened just after 4 p.m. on Ocean Avenue and Lee Street in the Ingleside District.
Video in the media player above is from a previous update
The victim was taken to the hospital with life-threatening injuries where he later died.
There is currently no word on what led to the incident.
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Investigators say officers located a suspect and arrested the 29-year-old man a few blocks away.
Anyone with information is asked to contact SFPD at 415-575-4444 or text a tip to TIP411 and begin the message with SFPD.