the attacker? >> hi, pamela. still so many questions remain following friday's hostage situation-turned deadly shooting here in california. and while there is so much we don't know, we can be sure this will be a lengthy investigation. one question law enforcement officers are currently working to answer is, what was the motive? what made this decorated army veteran engage in such deadly action and take three innocent lives? now, cnn has learned that some time before the shooting, the gunman made some type of threat against one of the victims. the details o s of that threat remain unclear, but it does help answer the question as to whether the shooter possibly knew any of his victims. authorities will be looking into the role any mental health issues may played, especially stemming from possible posttraumatic stress. went we have issues of mental health involved, there will always be a question of whether the gunman should have had access to firearms in the first place. cnn has learned from police officials that he had at least seven firearms registered in his