TODAY | April 19, 2013
>>> a note and i'll look at it. two people now in custody, nbc is reporting, at 410 norfolk street. this is in this watertown area. very near as i understand it to the live picture we have been showing you. two people who are in custody -- let me make a distinction. that doesn't mean they're under arrest. we're trying to be transparent with our viewers as we get information. things do change in a fluid situation like this. to be honest about it, we don't know anything about the motivation of these two brothers who police say carried out this attack on the boston marathon on patriots day , monday. let's get to lester holt . he's been watching the scenes unfold all night long. he's in watertown . lester, good morning again.
>> reporter: good morning, savannah. i won't lie. everyone here is a little on edge right now as the activity seems to have upticked a bit. you mention the no-fly zone. police are the exception and they have brought in the chopper a short while ago. first one we have seen today largely because of the inclement weather earlier in the day. the chopper was over us for a short time. he's back into orbit. the activity you have seen with s.w.a.t. team movement is roughly in that direction several blocks from us. much of this area has been shut down and this has been the route they have been bringing reinforcements. police from boston and state police and others as they really kind of enforce this notion that no one gets out of here. these are densely packed neighborhoods. old community, backwards butt against each other. difficult terrain for s.w.a.t. teams. they have to move very carefully and methodically and work in coordination with each other. in some cases you have multiple different police departments working together on this one mission. it's a very methodical process. there continues to be the threat to not only you are dealing with someone that has a gun but also an explosive as we know they were used during the police chase that brought this whole episode to watertown in the wee hours of this morning. you hear the chopper overhead. for a while it looked like he was focused on a specific area over there and now he's resumed that orbit. we don't frankly see a lot of police. one officer on the street here that's just kind of keeping this open for emergency traffic. we're kind of on our own here as we're outside of the perimeter they set and we're watching with a sense of expectation.
>> lester holt in watertown , thank