(Portland, OR)  --  A woman accused of attacking a witness in a deadly hit-and-run investigation has turned herself in to the Clackamas County Sheriff's Office.  Deputies day 28-year-old Alysha Esser and her boyfriend, Kevin Derrick, assaulted and intimidated a witness.  Derrick is facing charges for causing a deadly crash in Milwaukie back in September and fleeing the scene.  He is currently in jail.