SAN FRANCISCO (CBS-SF) — A suspect remained at large Thursday after a shooting in a crowded downtown San Francisco parking garage.

Investigators said they believe the shooter and the victim knew each other.

San Francisco police Sgt. Michael Andraychak said officers responded to a reported shooting at a parking garage on Mission Street between Fourth and Fifth streets around 6:30 p.m. Wednesday.

Arriving officers found a man suffering from multiple gunshot wounds to his lower extremities, rendered aid to him and called for an ambulance.

A preliminary investigation showed the man was waiting to pay for his parking space at the garage lobby where the suspect shot him from behind.

Andraychak said witnesses told police the suspect was a black man in his 20s who fled from the garage.

Officers set up a perimeter, evacuated the garage and searched for the suspect on each floor. But they were unable to locate the suspect, who likely left the scene before officers secured the area.

The victim was transported to a hospital, where he was treated for injuries not considered life-threatening.

Anyone with information on the shooting is asked to call the police tip line at (415) 575-4444 or send a text message to TIP411 with “SFPD” at the start of the message.

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