Police declined to identify the victim, who was shot about 7:40 p.m. Saturday outside the family eatery in the 16900 block of Prairie Avenue.
Arriving officers found one man shot "numerous times in the upper torso" and about 200 people milling around, said Torrance police Sgt. Jeremiah Hart.
Potential witnesses "drove away in multiple directions," said Hart, leaving investigators to piece together the story.
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Hart said eight to 10 men believed to be gang members got into an argument.
"People say they were shouting, then started to fight, then during that fight someone pulled out a firearm and started shooting," said Hart.
It was unclear why the men were in the parking lot.
"It is not a place you would associate as dangerous," said Hart. "It is a place for families and kids."
Anyone with more information about the shooting was urged to call detectives at (310) 618-5570.