needed to do. this is a very complicated plot with a lot of international travel and i think it's wrong for us to just take the narrative it was all home-grown, done off the narrative. i just don't think the story's going that way. >> you're saying you've heard it couldn't have been made by them, meaning it couldn't have been made by them without instruction or couldn't have been made by them, period, someone else manufactured it, they were just carrying it? >> they said look, they said -- they said the pyrotechnics, taking them apart is extremely dicey. one spark could set this off. and someone had to go down to that area and test the signal strength from one of these toys. you just can't hope that it's going to go off if you stand a mile away or half a mile away. you actually need to test the signals. there are so many layers of complication in this, it almost suggests that somebody was standing over tsarnaev's shoulder and reminding him how to do this or telling him to, but that is pure speculation at this point. but that is certainly something the fbi is looking at and that's why it's moving so quickly to