Officers were called to the Colonial Village Apartments just after 8:30 p.m. after getting a call about a fight and gunshots.
When they arrived, they found three victims, according Mike Hirman of the Auburn Police Department.
A 39-year-old man was shot and killed. Another man, 23, was rushed to Harborview Medical Center with gunshot wounds. That man's injuries are described as "serious."
A third victim, a 30-year-old woman, had knife wounds on her hands, Hirman said. She was also taken to Harborview for treatment.
The three people arrested have been taken to jail in King County for processing, and police say they have recovered what they believe were the murder and attack weapons.
Hirman says there may be additional suspects.