investigation in his words in an exemplary fashion. our crime and justice correspondent joe johns is taking a closer look at how federal officials are responding to the tragedy. he's got new information. joe? >> wolf, from a justice standpoint, this case is still really in its infancy but the director of national intelligence is already heading up an effort to try to determine whether any signals were missed that could have prevented the boston bombing. with the criminal investigation of the alleged boston bombers still in full swing including the search for possible accomplices, tuesday president obama defended the government's handling of tamerlan tsarnaev, who the fbi investigated back in 2011. the intelligence community is now doing a review to determine what might have been done better. >> the question then is, was there something that happened that triggered radicalization and actual -- an actual decision by the brother to engage in the