Police say the violence broke out at about 1:45 a.m. outside the Sports Page on Auburn Way.
A fight broke out as a crowd of people was leaving the bar. Several people then pulled out handguns and opened fire,
Police rushed to the scene, where three people were found dead of gunshot wounds. A fourth victim was rushed to Harborview Medical Center in critical condition.
The victims all were in their early to mid-20s, said Cmdr. Mike Hirman of the Auburn police.
Hirman says police have taken a person of interest into custody for questioning, but that person has not been arrested.
Responding officers said the scene was so chaotic, they don't know how many more suspects there could be. There also could be more victims, Hirman said.
Investigators say they found a car full of bullet holes in Federal Way, but it's unclear if it's related to this shooting.
This is a developing news story. More information will be posted as it becomes available.