Some reports are saying he has had multiple contacts with known extremists. If that is true, yes this was a terrorist act. Whether it is proclaimed as such by this administration, i doubt it. That is a hard pill to swallow, a United States Marine turning terrorist while stationed on US soil.
It will probably be spun to say he is some kind of crazy person with a disorder. I really wonder what he is going to say for himself.
Either way, after trial he should be marched outside and a bullet put in his head.