Who suggested that the top portions remained intact until they hit the ground?
I did. I'm willing to admit I'm wrong on that, but I'm not seeing the proof in the photos presented so far. My assumption of the top remaining fairly intact is based on there being not too much happening that would cause it to break apart. The top remaining intact, or breaking apart is not proof one way or the other of explosives being used, so the point is really, uh, pointless.