"Like 30, 40 shots went off, then you heard the cops come, car taking off," said Richard Madrigal, a witness.
Shell casings littered the sidewalk and the street outside the restaurant.
"There were actually shots being fired as deputies arrived," said Lt. Pat Nelson of the L.A. County Sheriff's Department.
Nelson said police saw at least one shooting victim being loaded into a car and leaving the crime scene. Police stopped the vehicle and detained three men. Two of them had gunshot wounds.
One man was shot several times in the torso and rushed to USC Medical Center. Another man was shot in the face, and two women were hit in the legs.
Deputies detained about 40 bar patrons for questioning.
Police are trying to figure out how many shooters there were, and if any of the victims may actually be suspects. Deputies determined that not all the bullets were from the same gun.
"It would appear from the evidence that we've been able to look at so far that there were at least two guns involved," Nelson said.
One gun was recovered at the scene.
Investigators are hoping video surveillance for inside the restaurant will provide them with some additional clues.
Deputies said they have been called to the bar in the past for fights, but it's unclear what led up to this shooting.
The Sheriff's homicide bureau is handling the investigation because doctors have told police that the critically injured man may not survive. Anyone with information is urged to call (323) 890-5500.