very, very used to terrorism beyond the irish cause. from the jihadist cause. and we had gone through review after review about how do we keep people safe, especially in big crowded spaces. this is going to be a learning around the world about what happened and how do we minimize the chances of that happening again. >> vikram, we're told in our sources here is elaborate but specific, we're told by a junior u.s. law enforcement official who was briefed on the british investigation by british officials. and from that sourcing we have a reporting that they believe they have at least tentatively identified the bomber. they believe it's a suicide bomber. they found a body that they believe was the bomber's body, and they believe they may have a tentative identification who have it is. from what you know of the way uk authorities approach these things, and the type of investigation, the contours of an investigation like this, will