deval patrick does what no governor in modern u.s. history has ever done. he orders nearly a million people to stay home. the greater boston area shut down. heavily armed officers in watertown searched for the suspect, house to house. residents trapped in their homes, but anxious to talk, communicate by phone, text and the internet. >> all day long, we just kept looking at each other, my husband and i, saying, is this really happening? and we're watching the tv and it just felt like we were inside this strange nightmare. >> 6:08 p.m. officials tell residents the imminent threat is over and they're free to leave their homes. >> we do not have an apprehension of our suspect this afternoon, but we will have one. >> reporter: no one could have guessed how quickly that would happen. [ gunfire ] 6:55 p.m. 47 minutes after the order was lifted, shots fired. police converged on a house a half mile from where they had last seen the suspect more than

16 hours earlier. watertown resident dave henneberry had seen something suspicious in the boat in his backyard. >> he looks inside just under the tarp, sees a small pool of blood at that point. >> reporter: at least 12 more shots are fired as s.w.a.t. teams and a police helicopter take up positions around and above the boat. new pictures released by massachusetts state police today show what they say is the suspect hiding in the boat. under cover of darkness, a negotiator is rushed to the scene. and much to the relief of the nation, at 8:45 p.m., the suspect is captured. tonight, the area around the boat and the boat itself remain sealed off by police. lester? >> kerry sanders, thanks. and while the crisis is over, the investigation of what motivated the suspects is just beginning. nbc's national investigative correspondent, michaelis

isakoff, has spent the day looking into the matter. >> investigators are intensely focused on the background of the tsarnaev brothers and what drove them to terrorism. meanwhile, federal prosecutors are prepared to file criminal terrorism charges that could carry the death penalty against the surviving 19-year-old suspect. the younger suspect, dzhokhar tsarnaev, captured live last night, is under guard at a boston hospital. federal agents are waiting to question him. as soon as his medical condition allows, about whether he had any accomplices or overseas connections. authorities believe his older brother, tamerlan, killed in a gun battle early friday morning while wearing explosives strapped to his chest, may have instigated the plot and persuaded dzhokhar to join him, but why? the brothers originally from chechnya, were raised in the u.s., living in the same house, and seemed to fit in.

both were athletic. dzhokhar, a wrestler, and tamerlan, a boxer. who hoped to be on the u.s. olympic team. but in recent years, tamerlan had changed and became radicalized, according to his uncle, who says he then spoke to a family friend. >> he said there is someone who brainwashed him, some newly convert to islam. >> reporter: in 2011, russian intelligence, concerned about the threat of chech knowian terrorism asked the fbi to investigate tamerlan, based on information that he was a follower of radical islam and that he had changed drastically since 2010, according to an fbi statement. the fbi says a checked databases, interviewed tamerlan and family members, but quote did not find any terrorism activity, domestic or foreign. the fbi says it asked the russians for more, but never got answers. >> without any strong derogatory information, the fbi would still be limited in what it could do. >> reporter: in january, 2012, tamerlan flew to russia for six

months. within a month of his return, in august 2012, tamerlan set up this youtube account full of islamie jihadi postings, many in russian, reflecting his former life in chechnya. in this video, a radical prophecy. >> no one can stop the jihad. >> reporter: his parents say their sons are not terrorists and have been framed by the fbi. >> translator: somebody clearly framed them. i don't know who exactly framed them, but they did. they framed them and they were so cowardly that they shot the boy dead. >> reporter: federal agents are determined to find out what motivated tamerlan and his brother but congressionals have tough questions for fbi officials about whether they could have done more to stop them. the justice department has decided to have the younger tsarnaev questioned for the first 48 hours by a special high valued interrogation team without advising him of his rights to counsel under what it calls a public safety exception,

but senator john mccain and two republican colleagues tonight says that doesn't go far enough. they want tsarnaev treated as an enemy combatant under the laws of war. lester? >> michael isakoff, thank you. for more on the government's attempts to find out what motivated these suspects, we're joined by nbc's chief foreign affairs correspondent, andrea mitchell. in our washington bureau, andrea? >> good evening, lester. intelligence officials, the fbi, a global search for what motivated tamerlan tsarnaev's terrorism. was it chechnyan nationalism, at the white house today, the president met again in the situation room with his national security advisers. he was briefed by the fbi director and top counterterrorism officials and others for 0 minutes. an official tells us afterwards that so far, there is no evidence of foreign involvement, but they're looking. they also say they are getting good cooperation now from russia, with whom as you know the u.s. has had very rocky relations over the last few years. russia's president

vladimir putin spoke with president obama last night and the two leaders are discussing the importance of working more closely together on counterterrorism in the future. the fbi as you heard said after interviewing tamerlan at russia's request in 2011, they sought and failed to get more information from russia's intelligence and state security agencies, so a lot of questions still to answer. did these brothers join existing separate chechen factions? if so, why weren't they attack ing russian targets? why did they go after their new homeland, the u.s.? this is a big mystery. tonight the president is commending his federal officials, also state and local officials, but they are still asking why did someone who was already in the fbi's database get through the cracks. lester? >> all right, andrea mitchell, thank you. the police department of watertown where this all ended is only about 60 officers strong and over the last two days, it was tested in ways that even the biggest police forces will rarely or ever experience. this afternoon, i spoke with

watertown police chief ed devoe about the larger implications of what his officers accomplished. based on what you've seen now, the weapons, the fact they had other explosives, in your mind, do you think they were prepared to attack again somewhere else? >> oh, you know, i don't know for sure, but my gut tells me that yes. i mean, if they have another you know, pressure cooker bomb, they weren't saving that for the watertown police. they were saving that for something similar to the boston marathon. >> reporter: your officers may have stopped another attack. >> i strongly believe that. >> chief devoe says he gets choked up when he thinks about the cheers and thanks his men and women got from the crowds of grateful residents last night for their job well done. the suspect is being held and treated in the same hospital as some of the victims of monday's bombings, and a police officer who was injured. katy tur is at beth israel hospital here in boston with more on that tonight.

katy? >> reporter: good evening, lester. the suspect is in serious, but stable condition here at beth israel and yes, he is in the very same hospital as many of the people the fbi says he tried to kill. cheers of joy, to a moment of silence. the city of boston may be relieved, but it is still in mourning. for 8-year-old martin richard, for 29-year-old kris. camp krystle campbell, for bu grad student lingzi lu, and sean kohl years, the m.i.t. police officer shot and killed in his patrol car thursday night, just are 55 minutes before his shift would have ended. >> he was a great young man. he was wise beyond his years. his goal was always to become a police officer. >> reporter: his family writing our only solace is that sean

died bravely doing what he committed to do, serving and protecting others." then there are those still fighting to survive. officials say 33-year-old transit officer richard donohue was shot multiple times during the gunfight with the tsarnaev brothers in watertown, tonight, in serious condition. liz norden's two sons each lost a limb near the finish line. >> it was a nightmare. it's running between two hospitals, trying to be each of them as sick as they are or hurt as they are, it's, i couldn't be in both places at both times. it's a nightmare. >> reporter: today, 31-year-old paul opened his eyes for the first time since he lost his leg. >> well, for a lousy situation, i just thank my lucky stars they're alive, so it's a great day. feels like the first day of my life. >> reporter: liz norden's other son just you got out of yesterday another surgery today. as of now, there are 53 people still in the hospital. seven -- three are still in critic

critical condition and lester that does include a 7-year-old girl. >> katy tur with us in boston tonight, thank you. and when "nbc nightly news" continues on this saturday, as boston breathes a sigh of relief, heightened alerts of public events around the country today. and later, states of emergency as major flooding hits the midwest.

000 the relief that this frightening chapter may be over has not erased the sense of

vulnerability that this brought on, a reminder terror can strike anywhere, anytime, and the response was evident today at public events throughout the country. michelle franzen has that story for us tonight. >> reporter: at the run apalooza in asbury park, runners started the day with bomb sniffing dogs and police patrols. unprecedented measures for a foot race in this historic jersey shore town. >> we made sure public safety was a paramount situation here. >> reporter: all around the country, recreational events are on parallel track with a nation on guard. in california at the annual long beach grand prix, more manpower and vigilance to handle the 170,000 spectators attending the celebrity charity race. >> i do think the police presence is necessary. >> reporter: security experts say there are no credible threats, but the boston bombing stripped away another layer of innocence to everyday american life. >> it doesn't mean you cancel events, but you want to be

monitoring crowds. you want to have perhaps more dogs, more undercover agents. >> reporter: at miami international, a security director ordered everyone to pay even closer attention to their surroundings. >> to be on the lookout for any suspicious behavior or unattended bags. >> reporter: overseas, london will deploy more than 700 police officers for tomorrow's marathon, the first big race since boston. >> i've increased by policing operation with high visibility patrols. >> back in new york, a city used to being on high alert, nypd officers will be out in full force at two races tomorrow, including the annual 9/11 memorial 5k. >> whatever they have to do that's necessary. >> reporter: a new sense of security and a new normal taking shape. michelle franzen, nbc news, new york. when we come back here tonight, the latest on what may have caused that huge explosion in texas.

more than 5,700. overseas, a race against time in china after a devastating earthquake killed at least 157 people and injured more than 5,700. it happened overnight in sichuan province where a massive quake struck five years ago. nbc's ian williams now the latest from beijing. >> reporter: the powerful 6.6 magnitude quake struck shortly after 8:00 this morning. for a full minute, it shook towns and villages in china's sichuan province. this in an area where memories are still raw of a devastating quake five years ago that killed more than 90,000 people. the government immediately dispatched thousands of soldiers and rescue workers to the scene. though many roads in this

mountainous area were blocked. in villages near the epicenter, authorities said nearly all the buildings had collapsed. there were extraordinary scenes as rescue workers scrambled to free people trapped in the rubble. there were at least 700 aftershocks. excavators and heavy machinery are moving in, as well as tents, blankets and other emergency supplies. china's new prime minister has flown in to direct the operation. tonight, rescue workers are still struggling to reach some of the more remote areas hit by the quake, and the number of casualties seems certain to rise. ian williams, nbc news, beijing. an update on another big story we've been following this week, that huge explosion at a fertilizer facility in texas. the death toll remains at 14 with more than 200 people injured. nbc's gabe gutierrez now the latest in the town of west, texas, tonight.

>> reporter: today in west, texas, the agonizing drive home. three days after the explosion that changed everything. this afternoon, police allowed some residents to return to the blast area. >> i don't know i got a house there. i don't know what house it's going to be, what kind of shape it's in. >> reporter: with 80 homes damaged or destroyed, the president has declared a state of emergency. >> and i want them to know that they are not forgotten. >> reporter: the death toll includes five firefighters and four emergency medics. >> it's pretty bad. we've got a lot of firemen down. >> reporter: off-duty firefighter kenny harris saw the initial flames and rushed to help the volunteer fire department. >> he was my best friend. we -- we did everything together. >> reporter: 96-year-old adolph lander had been inside a heavily damaged nursing home. he survived the explosion, but then his heart gave out. >> my dad died when i was 3

months old, so he was the father figure in my life. >> reporter: in a written statement the fertilizer facility's owner, says we pledge to do everything we can to understand what happened. already, some lawmakers are asking whether chemical storage regulations should be strengthened. >> those are legitimate and appropriate questions to be asking. >> reporter: a state filing last year shows the fertilizer facility had more than 540,000 pounds of ammonium nitrate. federal officials are looking into whether that amount should raised red flags. gabe gutierrez, nbc news, west, texas. in parts of the midwest tonight, flood season has arrived with a vengeance, leading to at least two deaths and putting thousands of homes and businesses under water. not far from chicago in des plains, the river hit record levels, forcing dozens of evacuations and causing floodings in more than 700 buildings. up next here on "nbc nightly

news," the spirit of boston, in this city and beyond.

in another time, it was the 11-month siege of boston that marked the beginning of the revolutionary war. tonight, this city has emerged from another siege, showing the world it won't back down from another challenge in this day and age. nbc's anne thompson joins me tonight with the spirit of boston alive and well tonight. >> it certainly is lester and you know how boston

loves its traditions from the marathon to the swan boats to the songs they sing at fenway park. well, this week, the nation adopted some of those traditions and it's helping the city move forward. today, boston looked the same, but it is not the same. children still flocked to mrs. mallard and her ducklings in the public garden, but parents are not as carefree. rich and and yvonne brought 2-year-old dylan with a mixture of relief and reservation. >> it just felt wrong that this happened to us. >> reporter: at fenway park -- >> get your free believe in boston flag with today's program! >> reporter: going to today's red sox game was an act of defiance. >> we don't back down. >> we were all talking about that last night, regardless of what happens today we're going to come to the game anyway. we just don't want those types of activities to run our lives. >> reporter: today people weren't just red sox fans, they were boston fans. like bo griffin who brought his family from south carolina.

>> believe in each other and we care for each other and boston is strong, it's symbolic of that, whether we're from south carolina or massachusetts. >> reporter: even the team itself showed its pride in the city, wearing special jerseys that replaced red sox with boston. >> and nobody's going to dictate. stay strong! >> reporter: boston strong is now a rallying cry across the country. at a road race in asbury park, new jersey, still recovering from superstorm sandy. on the iconic gold helmets of notre dame's football team during his spring game. and in major league ballparks. fans sang the red sox anthem, "sweet caroline," when word spread the suspect was in custody. led by neil diamond. ♪ sweet caroline ♪ da, da, da ♪ good times never so good

♪ so good, so good, so good >> reporter: but good times that will never be quite the same. april 20th is an important day in boston history. it's the day fenway park opened, the day ted williams first swung a bat for the red sox, and today, it's the day when victory was in more than just baseball. lester? >> you win. best assignment of the day. thanks very much. that's "nbc nightly news" for this saturday. i'm lester holt, reporting from boston. i'll see you tomorrow morning on "today," then of course tomorrow night. good night, everyone. thanks for being here. -- captions by vitac -- www.vitac.com

the search for answers continues today in boston after the second bombing suspect was captured as the world watched. good evening. i'm diane dwyer. president obama called in his team today for a 90 minute meeting in the situation room. they are answering the lingering questions about the attack and motive. this photograph was released, a night image showing the body heat from the is the-year-old dzhokhar var november hiding in a boat. >> crazy to think it was in this neighborhood and, you know, having facen the police and that everything was going to be okay. it's surreal, very surreal. >> i'm happy with the fact that

everybody was, you know, they were able to catch these guys quickly. >> that neighborhood is slowly returning to normal in the wake of a manhunt. investigators are combing through the quiet street where he was hiding last night. there's word he kept up what appeared to be a normal life after the bombings. we begin with jay gray in boston with new information on how the manhunt came to an end. jay? >> reporter: good evening, the day after a search that shut down america's biggest city, boston came out from behind the locked doors. we begin to learn more about how the intense stand off finally came to an end. hundreds of police rushed in after a call from a homeowner who noticed something different about the boat in his backyard. it was a massachusetts state chopper that first spotted dzhokhar tsarnaev.

he was alive and hiding inside the boat. we are learning how the search for the most wanted man in america finally came to an end. agents rushing in engaged in a stand off for more than 90 minutes. negotiators shouted to him to come out on your own terms. minutes later, he was in custody. today, he remains in serious condition in the hospital where authorities say he could be charged for terrorism and murder and questioned by the fbis elite high value suspect interrogation team. the fbi will focus on threats that he might be aware of. are there other devices? were other people working in the network? >> reporter: as the investigation continues, so does the push toward normalcy here. >> we don't want activities to run our lives. >> reporter: it's bee