Police were called to the Kmart, located in the 9600 block of State Avenue, at around 6 p.m. after getting reports that a possibly-armed man was threatening people.
Employees told police a customer was browsing the sporting goods section when he overheard workers talking about their normal security routine. The employees weren't talking about the man, but he apparently felt otherwise.
The man became very upset and threatened to "shoot everyone in the store," according to Commander Robb Lamoureux with the Marysville Police Department.
Police and Snohomish County sheriff's deputies flooded into the area and surrounded the store, but were unable to find the man.
Surveillance video shows the man walking out of the store, but police don't know if he left the area on foot or in a car.
A woman who was in the store when the action unfolded said employees didn't tell her what was happening, but told her to leave immediately.
"I was getting ready to pay and the lady said, 'Ma'am, drop your cart, get out of the store, there's cops," and I walk out and they've got the big guns," she said.
Lamoureux described the man as being white and heavy set. He stands about six feet tall and was wearing a grey button up shirt and a black bandana on his head. He may have been with a heavy set woman with blond, shoulder length hair.