(Douglas County, OR)  --  Police are investigating a crash that killed one person and injured three others in Douglas County.  Oregon State Police say the wreck happened around two o'clock Saturday afternoon on Highway 101, four miles south of Reedsport.  A vehicle traveling north crossed the centerline and slammed into an oncoming car, killing 40-year-old Heather Walseth.  Three other people are being treated at hospitals.