I am thinking enemy action more than false flag. That's why they were not sufficiently prepared for it and there seemed to be no double agenda when the drama was unfolding. There were no prepared statements, things happened in real time and the level of confusion among the government types tells me they had little or no foreknowledge of what was going on.

I figured there was some sort of foreign intelligence agency "warning" at some point, but we are talking about the FSB here, the organizational descendents of people so frequently so incredibly full of shit they make Alex Jones look mainstream.

If the FSB told me the sky is blue, I would go out and look just to make sure.

All they had done was put the Tsarnaev brothers on some sort of list, that's it. The FBI checked it out, and that was years prior to any attack, which means quite likely, back them, the brothers had no plans for a terror campaign but put together their plan later on.