TODAY | April 18, 2013
>> have news on the boston marathon bombing investigation. this morning, fbi agents are making significant progress thanks to surveillance photos taken at the site of the blast. pete, what can you tell us?
>> matt, good morning. the fbi is eager to identify, find, and talk to two young men, including one wearing a baseball cap backwards. he displays the behavior they're looking for. someone who walks up to one of the spots where the bombs were left, leaves a backpack behind and walks away just before one of the bombs goes off.
>> reporter: the fbi says it has pictures from several different sources showing the same thing happening at the spot where one of the bombs exploded. the sequence of explosions, 13 seconds apart can be heard on this videotape of universal sports network technicians making final preparations to cover the end of the marathon event. a key image investigators say was captured by a surveillance camera with a bird's eye view mounted high up across the street from the second bombing site. officials say it shows a young man talking on his cell phone who sets down what appears to be a heavy backpack and dashes away moments before the second bomb goes off. because he was on a cell phone , investigators are checking the logs of the hundreds of people using their phones in the moments before the bombing that might help identify who that person was. it's that second bombing spot seen in this picture sent to nbc boston station whdh showing a garbage bag next to a mailbox. while investigators can't be sure that bag contained a bomb, but that is the spot where the second bomb went off. former atf bomb investigator says it's obvious.
>> large injuries were on the side of it, debris field to the left. some protected areas over on the right side that indicate the blast was to the one side of the trash receptacle. this was the scene of the blast.
>> the fbi has considered publicly showing the pictures of the men they're looking for, but for now has decided to hold off on that as long as they believe they're making progress in finding them, savannah.
>> pete, let me ask you a question. there's a photo circulating on some news sites, shows two men, one of whom is wearing a baseball cap . and the question is being asked whether or not this may be the suspect that the fbi is looking for. we are not showing the photo because we are not aware of its relevance to the investigation if any. what are you hearing about that?
>> i'm hearing it may be the people that i've talked to that have seen different versions of the pictures, in one of them, for example, the man with the baseball cap is wearing it backwards. so before we're absolutely certain and show the picture, we want to make sure it's that picture. and they may end up showing the pictures themselves publicly. and if they do, they'll show much clearer pictures, savannah.
>> thank you very much. and