(Portland, OR)  --  An investigation is ongoing in Washington County after a woman allegedly shot her estranged husband to death in self defense during an argument.  Sheriff's officials say the woman called 9-1-1 yesterday to report the shooting at her home on Northwest Germantown Road.  Police say the couple was going through a divorce and that the man had come over to collect his things.  The woman says they began arguing and he pulled a gun on her, prompting her to pull out her own gun and shoot him.  First responders tried to save the man, but he died at the scene.