Las Vegas police Capt. Curtis Williams said Monday that investigators were trying to locate a tall, thin black man about 17 to 23 years old, who was seen fleeing the scene on a video surveillance tape.

"We know he had some connection with it. Exactly how — that's still an ongoing investigation," Williams said. Police said they would release a photograph of the man Monday afternoon.

Just after 3 a.m. Sunday, two men bumped into each other and started arguing, police said. Soon a fist-fight broke out and escalated into a brawl between two groups outside the Margaritaville restaurant and O'Shea's casino.

About 20 people threw bottles and cans at one another, then one man "pulled out a gun and fired four to five shots," Williams said.

Four people were injured in the shooting, none of them connected to the brawl. One woman, a female tourist from California, had a bullet removed from her leg and was recovering at a hospital. Three people were treated and released.

Investigators said they did not know whether the shooter was a gang member, but the two men they questioned and released because they matched the shooter's description — a black man wearing baggy pants and a white T-shirt — had some gang affiliation. Police think all those involved in the fight were area residents.

Williams said the shooting was an isolated incident and added that his department takes security on the Strip "extremely seriously."

"Everyone that was involved in that particular incident — the crime we believe they committed — will have charges brought against them," he said.

The weekend incident was the third shooting at a Strip casino in the past two months.