The shooting happened just before 4 a.m. in the parking lot behind a bar located in the 12600 block of Renton Avenue South, according to Sgt. DB Gates with the King County Sheriff's Office.
Five people -- both men and women -- were hit, but Gates said only one of the victims has life-threatening injuries. The others are being treated at local hospitals.
Details about the shooting are still sketchy, and Gates said the victims are not cooperating with police.
"Our understanding is that it happened in the parking lot," Gates said. "The club was either closing or had closed. A lot of people were milling around the parking lot, and that's when the shots were heard."
Evidence gathered at the scene indicates at least two guns were used in the shooting, and investigators aren't yet sure if the shooters were in a car or on foot.
"It's absolutely a possibility that this is gang related, and that may be why no one really wants to tell us what's going on," Gates said.
Detectives are still looking for witnesses to the shooting, and they'll also look at surveillance footage from nearby businesses to get a better idea of what sparked the melee.