A gunman remains on the loose after opening fire in a crowded mall north of Seattle, killing four women and critically wounding a man.
Police say they are searching for a Hispanic man wearing black and armed with a rifle who was last seen walking toward Interstate 5.
"We are still actively looking for the shooter,'' Washington State Patrol spokesman Sergeant Mark Francis said at a news conference.
"Stay indoors, stay secure."
Authorities say the motive is unknown.
The FBI is helping local authorities as dozens of police officers searched for the shooter.
The FBI's Seattle office said on Twitter that it "has no information to suggest additional attacks planned'' in Washington state but did not elaborate.
Authorities had initially said four people were killed, then said three were dead, before revising the number again. Francis said the number fluctuated as authorities searched the large Cascade Mall in Burlington.
He said the victims were shot in the makeup department of the Macy's store at the Cascade Mall in Burlington, about 97km north of Seattle.
Tari Caswell told the Skagit Valley Herald she was in the Macy's women's dressing room when she heard "what sounded like four balloons popping".
"Then I heard seven or eight more, and I just stayed quiet in the dressing room because it just didn't feel right. And it got very quiet. And then I heard a lady yelling for help, and a man came and got me and another lady, and we ran out of the store,'' Caswell told the newspaper.
Stephanie Bose, an assistant general manager at Johnny Carino's Italian restaurant near the Macy's store at the mall, said she immediately locked the doors to the restaurant after hearing about the shooting from an employee's boyfriend.
"He was trying to go to the mall and people were screaming,'' she told The Associated Press. "It was frantic.''