(Hillsboro, OR)  --  Washington County authorities are looking for a convicted sex offender who's failed to report to his parole officer.  Officials say 26-year-old Robert Edward Foster was recently convicted after he was accused of sexually assaulting a woman in a bathroom on the Portland State University campus.  Deputies say Foster served 90 days in jail, but his current location is unknown.  He's described as white, standing six feet tall, weighing 170 pounds, with brown hair and eyes.