Investigators are trying to determine the cause of a fire that damaged a portion of the Lake Stevens Boys and Girls Club on Monday afternoon. Investigators are calling the fire 'suspicious.' The fire started at approximately 2:30 P.M. Monday, investigators said. When firefighters arrived on scene, they found two portable bathrooms on fire. Flames had spread to the overhang and the roof of the building nearby. It appears the fire started inside the portable toilets, the Assistant Fire Marshal for Lake Stevens Fire told KOMO News on Monday night.