you look at this from a distance and you'd see, well, this is not a very cleverly made device. it's very common. but what the bomb technicians say is, yes, but, whoever built these managed to get them both to go off within 15 seconds of each other. and that suggests certainly some level of knowledge or -- or sophistication if you will. so they've taken all those pieces, chris. here's an interesting piece of data. the control tests have shown that after you blow up something like a pressure cooker bomb, the pieces are not consumed by the explosive. they're just made into thousands of pieces and spread all over the place. it is possible to recover 98%, 93% to 98% of them. that's why they've all been shipped here to the fbi crime lab, trying to keep them separate, which device they think is which, and they will try now to reassemble them, reconstruct them so they'll learn more about how they were made. you know, one unfortunate point