Sorry, but I don't buy that. The very same comment was made during the mailbox bombings here in the Midwest. "A single person couldn't being doing all of this... blah, blah, blah." (I'm an outside salesman. I remember stating to my wife that that circuit would be quite easy for a single person. Sure enough, it turned out to be a single, not-so-smart, college student pulling off the bombings.)
I agree that this is some form of terrorism. It could be international or domestic. Regardless, what has been happened so far could easily be achieved by a single person. What "resources"? .223 ammo is cheap. Gasoline is cheap. What in this case would indicate any large investment of resources?