What would they blow up the second time that the initial explosion would not have taken care of? Not saying that I believe in any conspiracy stuff, just wondering what is actually going on.
Also, here is a map for those of us who have never been there. The biology center near where it happened is #31 on left side of map.
I think I read that they blew up the guy's backpack. Just to make sure nothing was in it also. Apparently, according to their reports there was no bomb in it.