Mid-Columbia Fire and Rescue officials are investigating both the Sunset Valley Fire and the fire at the Port of The Dalles Marina to determine causes, but Chief Bob Palmer warns it’s a challenge to come up with definitive answers because the fire itself can destroy evidence.  He says often they can rule out causes, and come up with the most probable cause.  Palmer notes the nature of the marina fire being on water complicates that investigation.  Palmer adds the Office of the Oregon Fire Marshal is assisting in the Marina investigation, and there are several insurance companies involved as well along with Special Districts of Oregon.  The Wrentham Market Fire is being investigated by the state fire marshal’s office.