Authorities first received reports of suspicious circumstances about 9:35 p.m. Sunday.
"When officers arrived there were still shots being fired," said Federal Way police spokeswoman Cathy Schrock.
After police flooded the area and carried out searches, authorities said they were confident there were no more casualties from the shooting.
By dawn, a King County medical examiner's office truck arrived at the scene to pick up bodies. Crime scene investigators continued working. One officer was seen carrying books and a gun to what appeared to be an evidence van.
A total of eight officers fired their weapons, Schrock said. All have been placed on administrative leave, per standard policy, as the investigation continues.
Wilson said the investigation was ongoing. He said the suspect, who had a valid concealed weapons permit, had no criminal history. However, Wilson said officers had responded to two prior domestic violence calls in Federal Way and Seattle. Both incidents were verbal in nature and no arrests were made, Wilson said.
Federal Way is about 20 miles south of Seattle.