(Vancouver, WA)  --  Police are releasing the identity of the officer who shot a teenage boy to death in Vancouver, Washington.  The Vancouver Police Department says 48-year-old Corporal Roger Evans shot and killed 16-year-old Clayton Joseph Tuesday night while responding to a domestic disturbance call at an apartment complex at 10th and Southeast Ellsworth Road.  Police say Joseph and another person were fighting in the parking lot and that Joseph was holding a knife.  Corporal Evans says Joseph refused to drop the knife and did not comply with his orders, so he shot him.  Family members say Joseph was trying to stop the fight when police intervened and that he was not the agitator.