Uhhh, what just happened? Following a tragedy like this so many people say how "it may have happened because the person was mentally ill" and how we "shouldn't judge" because the person may have been mentally ill. Seriously? The police and FBI KNEW this guy was mentally ill! He had gone to a mental health facility following a "mental health crisis" where he was convinced his mind was being controlled. The police had has multiple encounters with this person over many months time. 
Then they gave the gun they locked away from him for safe keeping, back to  him. Why? This is not a matter of a nanny state or NRA overreach or anything like that. This is a case of a person with recent mental illness documentation and actions of domestic violence owning a gun. This is the very person who shouldn't own a gun. He's not someone who simply takes antidepressants or the like, he is a mentally ill person who acts out and therefore should not be allowed to possess firearms.