joining me now is former fbi profiler and nbc analyst clint van zant. good morning to you. the question might be what's the next committee step in this investigation? >> well, the investigators have got a lot going for them, richard, as far as forensic evidence and otherwise. as you know, law enforcement sources suggested at least two unexploded devices have been found. that's magic for investigators right now. notwithstanding forensic evidence, fingerprints, dna, hairs, fibers. they'll also see how the device was built. they'll be able to see what the components are. they'll be able to trace those components back. we're told that these are relatively unsophisticated low-order explosive devices. richard, that's something like if we think back to the olympic park bombing in 1996. >> right. >> those pipe bombs filled with black powder with shrapnel in or packed around them. that's the type of device. and realize in this case, where a bullet, let's say, for example, moves at about 1,000 feet a second. that low-order explosive, when it went off, it would still be pushing those

clint van zant, fbi veteran profiler. what can you add, clint? >> well, as you know my background is as a hostage negotiator. having been in similar situations like this working with tactical teams, this is a hand in glove operation. the negotiator is on the scene. he or she will be working hard to extend a hand and allows this individual to come out. with the potential explosive device of something inside the best case scenario would be for the negotiator to get the subject to come over the side of the boat, crop to the ground so that the tactical team. anything like that. then they can close, make the arrest and then administer first aid. it's going to have to work like that. they are not going to endanger a police officer or agent in the arrest and have this guy try to blow himself up at the last second. >> we have been circumspect because there's been so much reported wrong over the past couple of days about passing things along. this does make sense though. boston globe is tweeting out that one of the photographers is in close enough to be a

. >> all right, former fbi profiler clint van zant. we just want to bring viewers up to speed on where things stand right now. a number of developments. a tremendous amount of activity over the course of the last few hours and here's where things stand at this time. one of the suspects in the boston marathon bombing is dead at this time. one of suspects at large. that suspect was referred to as suspect number two, shown in photos wearing the white cap and fishlts say that he's believed to be armed and dangerous. they're advising the public to use extreme caution and advising massachusetts residents to stay indoors and not answer their doors. a human toll here, one police officer was killed overnight in a shootout with this man. story. stay with us for more. >>> good morning. lester holt in watertown, massachusetts, after a dramatic night, the two men suspected of carrying out the marathon bombing in boston on monday have apparently led police on a wild chase, a shootout. this morning, one is dead, another is at large. place here in wat

clint van zant is a former fbi profiler, also an nbc analyst. s cavanaugh is a retired atf special agent, also an msnbc and nbc news analyst. thanks for coming back, guys. let's start here, clint. at this point, where are federal investigators likely to focus their investigation to determine whether these brothers, in fact, acted alone? >> you have got some immediate things they have got to do and they have got some long term. we want to assure all the investigative agencies and especially the public in the boston area there are no more devices, nothing out there with a two-week timer sitting on it or anything like that that these guys might have set. not only did they built the pressure cooker bombs but told happened held ieds, pipe bombs. and find out if anybody in the area was supporting them in the activities, the investigations go on from there. where did they get the training? investigators in their own mind are comfortable that the 26-year-old was the leader, the 19-year-old was the follower. but where did the 26-year-old get his inspirati