Dateline | April 24, 2013
>>> with a possibly armed fugitive on the loose, watertown police took unprecedented measures last friday and were forced to make extraordinary decisions.
>> you got to get out of here!
>> regarding public safety .
>> move, move, move!
>> it's important folks remain indoors.
>> after a night of terrifyi ining gunfire, the governor announced a lockdown of watertown and nearby towns and then expanded it to all of boston. the transit system was shut down, schools and businesses closed. as authorities ordered more than a million people to stay indoors. all of this, to find one man.
>> i was scared. it was kind of surreal. i didn't really believe this was happening in my town and, you know, i couldn't really figure out what was going on.
>> law enforcement flooded watertown , and zeroed in on a 20-block zone to search for dzhokhar tsavraev. at times it seemed the only people on the streets were members of the media.
>> i was standing here all day while s.w.a.t. teams were going house to house. in your gut, did you think you would find him in this town?
>> after we pinned him down, i kind of did. the 20-block perimeter. we were fairly confident he was inside that.
>> but where? morning turned to afternoon with no sign of the boston suspect, had he managed to hop a train before amtrak service was shut down? and then after 6:00 p.m ., a surprise announcement. one that seemed more curious than calming.
>> the stay indoors request is lifted. the t is open effective immediately. transf .
>> it raised a big question. why did authorities allow people to leave their homes as night was falling? had they given up, or was it a tactical move? boston police commissioner ed davis . on friday the search was going nowhere , but a killer still on the loose. were you hesitant about lifting the knockdown?
>> we hesitant about everything we've done, making the best decisions we could. i can't get into details as to why we decided to lift it, but we did. thankfully. when the citizens started to move around, we found the suspect.
>> they found him only after one of the average citizens cracked the case. just less than an hour after the lockdown was lifted, one watertown resident stepped into his backyard. and saw something strange on his boat. he described the scene to his stepson.
>> small pool of blood, as if someone had either -- i say someone. you know, being -- putting myself in his mind, i would have thought, hey, i haven't had this boat open all winter. did an animal crawl in and die? is it a squirrel?
>> it wasn't an animal, it was a human, it was taken overhead. it touched off the next wave of chaos. rebecca krieger so frightened during the night during the shoot-out, was now a few houses down from the center of the action.
>> it felt a lot like a war zone in watertown .
>> she took to social media to tell the world what she was seeing with photos, showing the havoc one young man has called in his town.
>> he is moving. we have movement in the boat.
>> police brought in an fbi negotiator to talk to dzhokhar tsavraev. who was lying in that boat, wounded. finally, he surrendered. and was placed in an ambulance.
>> we saw the ambulance drive away. and that was when we knew and we started -- you know, phones blowing up again, they got him, it's all over.
>> that subject is in custody. he is in custody at this time.
>> but even in the euphoria of that night, law enforcement officials had come to a frightened conclusion, the bombers had other targets in mind. the evidence? the bombs the suspects had deployed during the fire fight.
>> my gut tells me, yes. they had another bomb, they weren't saving that for the watertown police. they were saving that to do another event similar to the boston marathon .
>> your officers may have stopped another attack.
>> i strongly believe that, yes. they had weapons and bombs and were going to use them.
>> was the boston marathon their last target?
>> i don't think it was. they were going somewhere and had evil intent.
>> if a plan for regular bombings had been foiled, regular civilians played a role in stopping it. to the tips called in, the photos, and the man who went in his backyard and bumped into an alleged bomber. the fbi can get closer to answering the big questions . what drew the tsavraev brothers to this attack? had they acted alone?