different people and variables. cnn analyst, former assistant homeland security juliette kayyem joining us. let's pick up something fran said there. when you look at this, how does this rate as a difficulty factor for an investigation? tons of people? cell phone communication, closed circuit tv, everybody has a device these days, lots of eyeballs on the situation, and yet also so much to go through. how do you balance it? >> overall, it's going to be pretty good for the investigation for the reasons you said. this was a high-profile event, lots of cameras, potentially eyewitnesss, we'll have to cull through that, see who knew what, saw what, maybe didn't know they saw something. up somebody came in. you have the cameras and the bomb material. >> following up with the cell phone information, it tells us who was talking to whom, but may relate to detonation? >> potential detonation.