No, he wasn't middle-eastern, but so what? He could have an Arab wife. He could be a nut case copy-cat.
He could be some nut-case finge group member that has allied themselves with the Islamic terrorists. That is a possibility. For example, what if some of the anarchists have decided to throw in with al Quaeda, because they share the common goals (anti-western culture, anti-trade, sismple living, etc.)? There could be TWO groups of terrorists at work, with different goalas but common methods.
It occurs to me that this guy looks like someone about my age who never left the sixties. There are some people like that, and some of them are scary.
Call the FBI. Let the burden of deciding be on their shoulders, not yours. I would call, myself.