A man shot and killed by Portland police Monday night on the top floor of a parking garage in northeast Portland was armed with a shotgun and fired at officers before they returned fire.  Sergeant Pete Simpson says officers got aid to the man as quickly as possible.  The Medical Examiner has identified the man as Santiago Cisneros, III, 32.  The officers were not injured; one is a four year veteran of the Police Bureau and the other is a 10-year-vet.