"So ... the next dot would be if we got a third tape."
I don't think there will be another tape before a hit. If they can assassinate any big cheese they will, but even that might not occur prior to a major hit. The job now is to snag them before they can assassinate and snag them before they can trigger anything. We are down to hours, a day or two at most.
Church ... actually, the third tape would go to major network reporters, so that they could film the terrorists straping on bombs, or setting off the explosion or whatever ...
Assuming that the first one is not a hoax.