let's bring in retired atf special agent, jim kavanaugh. thank you for coming on. is this a low level terrorist act, it has no significance beyond we live in a free society and occasionally we get a bad person who wants to make some sort of hideous statement? >> he's a mad dog loser and we're always going to have these guys as you were discussing with shawn and that's true. but chris, i like to think that there's complicated things that we can do that our intelligence enforcement do, our wire intercepts, all those things are complicated when we need to do better at them but there's simple things we can do too. should we really have long pedestrian malls, pedestrian malls now that are frequented by pedestrians and bias kicyclers. when you look down the views of the camera and see that long stretch, that's only for pedestrian use. that can be defeated in the future by some boulders, three boulders across that stretch can keep a vehicle like that from accelerating. >> how about tiger teeth? >> sure. there's all kinds of things they can put out there. when we say -- we

joining me now is jim kavanaugh. it's been nearly a week since the shooting. still very few clues on a motive. how much planning must have gone into this to leave just so few traces, and have you ever encountered a case like this from that perspective? >> this guy is a strange cat, phillip. there's no question that as we try to evaluate the motive, it changes as the facts change. it's just like at the command post on any big case. who is it, why are they doing it, what's driving it. we always have all those questions. early assessments, i thought maybe we had a gambler losing his murngs goioney, going to tr back at the world. that's been taken off the table by the new facts that this guy researched the hotels in boston and chicago and at concerts. so we have to look at the motive from inside him and the targets and his planning, like you say, and his purpose and see if we can, you know, get something out of that. >> we've heard the undersheriff saying they cannot confirm whether anybody else may have known about this incident before he carried it out. in polic