the crowd reacts to the first explosion. virtually every head turns toward the blast except for tsarnaev who virtually alone among the individuals appears calm. he glances to the east and starts walking rapidly to the west away from the finish line without his knapsack which he left where he was standing. ten seconds later an explosion occurs in the place where he left the bag. joe johns, cnn, washington. with one suspect dead, and the other who can only nod they are keep to talk to tamerlan s widow. she has been staying with her parents in rhode island. crise lawren chris lawrence is there with more. reporter: they are looking to get an answer as to what she