investigation says the suspects initially planned to carry out a suicide attack on the fourth of july. deborah feyerick joins us live from boston. deb, what more have we learned about this supposed plan to strike on independence day? and is there any evidence to support that? >> well, right now investigators are looking into this theory that in fact it may have been july 4th, but there's still sort of an absence of hard evidence to suggest that in fact that was their number one target. why they decided to change their plans. initially wi heard reports that they were building the bomb and they built it too quickly. they didn't realize how fast they would be able to build it. so they sort of moved up their plan to attack the boston marathon. people that i'm speaking to say they just don't believe that that's true because of the way they executed it in terms of what they call the trade craft, the way they sort of approached their target points, the time in between the detonations, the way that the whole thing was done pretty methodically suggested