There an exception to getting a warrant called the emergency administrative search rule. But that would apply more if there were leaking gas in an area and immediate action were needed. Here one could argue the same should apply. First, ever, if they were searching for a terrorist, they had no right to search people who came out of the house, because none of them was the terrorist. Second, unlike leaking gas, the cops had no real information about where the terrorist was. I do not believe the emergency administrative exception applied here.
Thanks for your good explanation rcofdayton. We worry about ‘what’ the laws are, but Obama and Holder will just do what they please, regardless.