Investigators from the Valley Regional Fire Authority have determined the cause of a Wednesday house fire in Pacific to be incendiary.

A juvenile male admitted to acts that caused an attic fire at a vacant residence.

Damage to the house is estimated at $75,000.

A passerby called 911 at 6:53 p.m. Wednesday after witnessing smoke and flames coming from the roof area of a home at 241 Valley View Drive. When VRFA firefighters arrived at the structure four minutes later, they found the attic area engulfed in flames with flames venting from the roof area.

As the fire was being knocked down, the roof became unstable and partially collapsed. Firefighters made entry and confirmed the structure was unoccupied.

Crews from four VRFA fire engines, two aid cars and one command unit were on scene and King County Medic One provided rehabilitation services for firefighters.