Yakima police say they believe firearms were stolen around the time a Bi-Mart caught on fire early Tuesday morning.
Authorities say the fire was set deliberately.
The burglary involved at least two people, police spokesman Mike Bastinelli said Wednesday. He added that video surveillance shows a third person in a vehicle may have been involved.
Police have not announced whether the burglars are suspected of arson.
Investigators say the fire caused more than $1 million in damage. Although the flames were confined to an upper storage room, the store filled with smoke, damaging merchandise.
The Bi-Mart will be closed while damage is repaired and merchandise is assessed, the Yakima Herald reports.