The cause of a truck fire Monday morning in rural Webster City is being investigated by the Webster City Fire Department.Webster City fire chief Chuck Stansfield said the call was received at approximately 8:41 a.m. on Stagecoach Road north of Highway 20. When firetrucks arrived, the pickup was engulfed in flames. No one was inside the vehicle with the driver not on the scene. The fire was quickly brought under control.The contents were removed from the bed of the truck and wet down and the inside of the cab as well. Reports from Hamilton County Dispatch stated that the driver pulled over due to smell of smoke, opened hood and found the vehicle on fire. The vehicle was investigated, no evidence was available to show how the fire was started. The fire appeared to start in the engine compartment, but the amount of damage did not allow for any further findings. The investigation is still ongoing, but nothing shows any intention of the fire being started on purpose.