(Vernonia, OR)  --  Authorities are investigating the death of a Hillsboro man who was reported missing in Columbia County.  The body of Jon Hill was found shortly after five p.m. yesterday, about a mile from where his pickup truck was found Sunday near Vernonia.  Officials say Hill went bow-hunting Saturday, and was reported missing after he didn't return home Saturday night as scheduled.  There's no word on possible cause of death.