Residents who fled the area where Dzhokhar A. Tsarnaev is believed to be in hiding were comforted. 
 
 WATERTOWN — Four days after two deadly explosions turned the finish line of the Boston Marathon into a scene of bloody chaos, the 19-year-old college student believed to be responsible for placing the bombs was taken into custody tonight, bringing a sense of relief and justice to a shaken region. 
 
 Dzhokhar A. Tsarnaev of Cambridge was pulled from his hiding place in a boat parked behind a house on Franklin Street shortly before 8:45 p.m. in this community just outside Boston. 
 
 “We are eternally grateful for the outcome here tonight. We have a suspect in custody,” said Colonel Timothy Alben, commander of the State Police. “We’re so grateful to bring justice and closure to this case.” 
 
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 “It’s a night where I think we’re all going to rest easy,” Governor Deval Patrick said at a news conference in Watertown. 
 
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 With the second suspect in the case, Tsarnaev’s brother, Tamerlan Tsarnaev, 26, fatally shot in a gun battle with police early this morning, Boston Police Commissioner Edward F. Davis said, citizens “can be confident that the threat has been removed.” 
 
 President Obama, speaking at the White House tonight, said, “We’ve closed an important chapter in this tragedy.” But he also said there were “still many unanswered questions” and said the FBI would thoroughly investigate. 
 
 Dzohkhar Tsarnaev, who exchanged gunfire with police from the boat, was rushed to a local hospital, where he was in serious condition, Davis said. 
 
 Police had approached him cautiously, worried that he might be wearing a suicide bomb vest. 
 
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 “We got him,” Boston Mayor Thomas M. Menino tweeted immediately afterwards. He took to the police radio to thank officers personally, telling them, “Good job, guys!” 
 
 The apprehension of Tsarnaev was the latest stunning development in a day of mayhem that had shocked the city, even as it was still reeling from Monday’s Marathon attacks. An MIT police officer was killed, “assassinated,” Thursday night in Cambridge. Then a carjacking was reported. Officers pursued the car, which turned out to contain the two Tsarnaevs, who threw explosives at them. 
 
 The elder brother was shot by police early Friday in a gun battle in Watertown, in which fficials said they wielded improvised explosive devices and homemade grenades. Dzhokhan Tsarnaev was so desperate to escape he ran over his brother as he lay wounded. He later abandoned the car in Watertown and fled on foot, disappearing from sight. 
 
 Law enforcement mobilized, sending legions of heavily-armed police officers to search a 20-block area of the community. At the same time, Governor Deval Patrick took an unprecedented security step, asking people in Boston, Watertown, and several other nearby communities — totaling a million people — to “shelter in place” — stay at home behind locked doors and open up only to police officers with proper identification. 
 
 Government and business offices closed as police cars zoomed on mysterious errands on deserted streets. The Red Sox and Bruins games were canceled, as well as the Big Apple Circus. Amtrak was shut down from Boston to Providence, as well as the MBTA, the Boston area’s public transit system. The region came to a standstill. 
 
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 Then, at 6 p.m., officials held another news conference to say that despite the massive manhunt, they had come up empty. The suspect had slipped outside their perimeter. Officials said they remained determined to find him, however, and that they believed he was somewhere still in Massachusetts. Patrick dropped his request for people to shelter in place and ordered the MBTA to resume service. 
 
 The dramatic finale came less than an hour after the news conference was over. A resident of Watertown came out of his house and noticed blood on his boat and that the tarp covering it was ripped. He lifted the tarp and saw a bloody form. He called police, who raced to the scene and exchanged gunfire with Tsarnaev, said Davis, the Boston commissioner 
 
 Police surrounded the boat and there was a standoff for about an hour and a half. A State Police helicopter peeked at him from above, using a special infrared camera. Police deployed “flash bang” grenades to stun and distract him, Davis said. Police were cautious in their approach, concerned that Tsarnaev could be wearing a suicide bomb vest. 
 
 A Globe photographer at the scene could hear police calling, “We know you’re in there. Come out on your own terms. Come out with your hands up.” 
 
 An FBI hostage rescue team was eventually able to pull him out. 
 
 In yet another twist in the story, New Bedford police said this evening that three people had been taken into custody in their city as part of the bombing investigation. 
 
 New Bedford Police Lieutenant Robert Richard said his department assisted federal investigators in executing a search warrant at a home on Carriage Drive, about 10 minutes from the University of Massachusetts at Dartmouth, where Tsarnaev was a student. 
 
 
 
 MIT Police Officer Sean Collier, 26, of Somerville, who was fatally shot while sitting in his cruiser near Main and Vassar streets in Cambridge, in what Davis called an “assassination,” was remembered as a brave and devoted officer. 
 
 MBTA Transit Police Officer Richard H. Donahue Jr., 33, who was shot as officers pursued the Tsarnaevs into Watertown, was in critical but stable condition at Mt. Auburn Hospital. 
 
 Scott Helman, Marcella Bombardieri, ­Brian MacQuarrie, Martine Powers, and Maria Sacchetti of the Globe staff and Globe correspondents Todd Feathers, Lauren Dezenski, Jeremy C. Fox, Haven Orecchio-Egresitz, Jaclyn Reiss, and Gal Tziperman Lotan contributed to this report. ||||| The two suspects in last week's Boston Marathon bombing weren't licensed to have guns, the Cambridge, Mass., Police Department confirmed Sunday. 
 
 Dzhokhar Tsarnaev, 19, who was captured after a gun battle with police Friday, wasn't old enough to be licensed to own a gun in Massachusetts. The minimum legal age is 21. 
 
 His older brother, Tamerlan Tsarnaev, 26, who was fatally wounded hours earlier, never had a license to own or carry a gun in Cambridge, where the pair shared an apartment, Cambridge Police spokesman Dan Riviello told the Los Angeles Times. It's unclear whether he ever applied for a license. 
 
 The pair's deadly, chaotic showdown with police that began Thursday night continued to come into focus Sunday as investigators plied through the brothers' lives before the bombing and their actions afterward. 
 
 FULL COVERAGE: Boston Marathon attack 
 
 About five hours after federal investigators published photos of the the two suspects taken at the Boston Marathon, police say, they killed a Massachusetts Institute of Technology police officer Thursday night and carjacked a Mercedes SUV nearby. 
 
 Cambridge Police told The Times that the Mercedes driver escaped when the brothers went inside a Shell gas station on Memorial Drive in Cambridge to buy snacks. 
 
 The unidentified driver fled to another gas station to call police. 
 
 Sometime later, Boston Police Commissioner Ed Davis told CNN, a police officer began following the Mercedes with the emergency lights off to wait for backup when the brothers stopped their car. 
 
 "They aggressively alighted from the car," Davis said. "They stopped their vehicle, they just stopped when they saw the car and attempted to get the officer.” 
 
 A hectic gun battle ensued, with the brothers and the responding officers trading more than 200 shots, Davis said. The brothers had three guns, police said. Further details about those guns have not been released. 
 
 PHOTOS: Manhunt in Boston 
 
 Dzhokhar Tsarnaev ran over his wounded older brother when police were about to arrest him, Davis said, though it has not yet been determined what caused Tamerlan's death. He was had gunshot and blast wounds. 
 
 An officer was critically wounded in the showdown. 
 
 The city of Boston was locked down Friday while officers searched for Dzhokhar Tsarnaev. By early evening, police lifted the lockdown, and a Watertown resident noticed that the cover was loose on the boat he stores in his backyard. As he tried to put it back on he noticed the cover was ripped and had blood on it. He lifted the cover and saw what he thought was a bloody body, Davis told CNN. 
 
 “All of a sudden, the body moved,” Davis said, and the resident alerted authorities. 
 
 A federal official said Dzhokhar Tsarnaev had been shot in the neck, complicating authorities' efforts to speak to him in the hospital. 
 
 PHOTOS: Explosions at Boston Marathon 
 
 Dzhokhar Tsarnaev remained hospitalized Sunday with a team of FBI interrogators standing by to interview him, Davis said. 
 
 He wouldn't confirm whether the brothers had outside help, but he said he believed they were the primary suspects in the bombing, which killed three people and left more than 170 injured. 
 
 Molly Hennessy-Fiske in Boston and Richard A. Serrano in Washington contributed to this report. 
 
 ALSO: 
 
 Blast site in heart of Boston getting back to normal 
 
 Video said to show suspect setting backpack down 
 
 Boston plays, prays and remembers on Sunday of renewal ||||| Brian Snyder / Reuters Police officers take position during a search for the Boston Marathon bombing suspects in Watertown, Massachusetts April 19, 2013. Police on Friday killed one suspect in the Boston Marathon bombing during a shootout and mounted a house-to-house search for a second man in the suburb of Watertown after a bloody night of shooting and explosions in the city's streets. REUTERS/Brian Snyder (UNITED STATES - Tags: CRIME LAW) 
 
 Boston and its suburbs, universities and transit system were on total lockdown Friday as police hunted door to door for marathon bombing suspect Dzhokhar Tsarnaev -- on the loose after his accomplice brother was killed in a stunning chain of events that left one cop dead and another injured, officials said. 
 
 During a desperate effort to flee after their photos were released by the FBI, the brothers carjacked a Mercedes SUV and told the driver they were the men behind Monday's double-blast attack at the race and had just killed a campus security officer, a source told NBC News. The driver was released unhurt. 
 
 The older brother, Tamerlan Tsarnaev, was killed after a wild chase and firefight, but Dzhokhar was still at large in a densely populated area, and an associate was being sought. Adding to the nightmare, an explosive was found in Boston Friday morning and disabled, an official said. 
 
 The suspects' uncle, Ruslan Tsarni, called them "losers" and urged Dzhokhar, a naturalized American citizen of Chechen origin, to turn himself in. 
 
 "We're ashamed," he thundered outside his Maryland home. 
 
 Three dozen FBI agents were surrounding the Cambridge, Mass., home where the brothers grew up after moving to the U.S. a decade ago, seeking asylum. They feared it could be booby-trapped and planned to conduct a controlled explosion before a full search, state police said. 
 
 NBC's Lester Holt reports from Watertown, Mass., where Boston and state police, SWAT teams and a helicopter are engaged in a tense search for a suspect in the Boston Marathon bombing who is still at large. 
 
 Across the area, as police cars screamed down streets and helicopters hovered overhead, authorities urged the public to stay inside and keep their doors locked to anyone but law-enforcement officers. 
 
 "There is a massive manhunt under way," Massachusetts Gov. Deval Patrick said. "We are asking people to shelter in place." 
 
 Subways and buses were shut down, and Amtrak service to Boston was cut. Harvard University, Boston University, the Massachusetts Institute of Technology and Emerson University were closed. The University of Massachusetts' Dartmouth campus was being evacuated because someone wanted in the case is registered at the school. 
 
 The lockdown initially affected more than 300,000 people in Cambridge, Watertown, Newton, Brighton, Allston and Belmont, but by 8 a.m., the entire city of Boston was paralyzed, officials said. 
 
 Watertown, where the second suspect was last seen, was the epicenter of a sprawling search. By 12:30 p.m., police estimated, 60 percent of the homes had been searched. Frightened residents were trapped inside as convoys of heavily armed officers and troops arrived by the hour. 
 
 The overnight violence began at MIT about five hours after the FBI released surveillance photos of two "extremely dangerous" men suspected of planting two bombs near the finish line of Monday's Boston Marathon, killing three and wounding 176. 
 
 Read more: Who are the brothers accused of the Boston Marathon bombing? 
 
 Tips about the identity of the suspects were still pouring in when the Tsarnaev brothers fatally shot MIT patrol officer Sean Collier, 26, in his vehicle at 10:20 p.m., law enforcement officials said. 
 
 Uncredited / AP FBI photos of the Boston Marathon bombing suspects, brothers from the Chechen Republic. The man on the left is dead. The man on the right, Dzhokhar Tsarnaev, is still at large. 
 
 The brothers then carjacked a Mercedes SUV, holding the driver captive for a half-hour while they tried to use his cash card to get money from three ATM's, a source said. At the first, they put in the wrong number; at the second, they took out $800 and at the third, they were told they had exceeded the withdrawal limit, the source said. 
 
 The man was released unharmed at a gas station in Cambridge, sources said. As they sped toward Watertown, a police chase ensued and the suspects tossed explosive devices out the window, officials said. 
 
 There was a long exchange of gunfire, according to Andrew Kitzenberg of Watertown, who took photos of the clash from his window and spread them on social media. 
 
 “They were also utilizing bombs, which sounded and looked like grenades, while engaging in the gunfight,” he told NBC News in an interview. “They also had what looked like a pressure-cooker bomb. 
 
 “I saw them light this bomb. They threw it towards the officers,” he said. “There was smoke that covered our entire street.” 
 
 A transit officer, identified as Richard H. Donahue, 33, was seriously injured during the pursuit. Authorities said he was in surgery at Mount Auburn Hospital. 
 
 Kitzenberg said he saw the firefight end when Tamerlan Tsarnaev ran toward the officers and ultimately fell to the ground. 
 
 Tamerlan -- the man in the black hat from FBI photos released six hours earlier -- had an improvised explosive device strapped to his chest, law enforcement officials said. 
 
 Dzhokhar -- who was wearing a white hat in the surveillance photos from the marathon -- drove the SUV through a line of police officers at the end of the street, Kitzenberg said. 
 
 Police said Dzhokhar has a Massachusetts driver's license and lives in Cambridge. He was described as light-skinned and with brown, curly hair, and wearing a gray hoodie. The FBI released more photos of him, including a surveillance camera photo from a 7-Eleven. 
 
 His father, in Russia, told the Associated Press he was "a true angel" and described him as a medical student who was expected to visit for the holidays. 
 
 Authorities painted a starkly different picture. 
 
 "We believe this man to be a terrorist," Boston Police Commissioner Ed Davis said. "We believe this to be a man who's come here to kill people." 
 
 Armored humvees and busloads of law-enforcement could be seen rolling into Watertown in the hours after the gunfight. 
 
 "We've got every asset we could possibly muster on the ground right now," Patrick said. 
 
 Later Friday morning, attorney General Eric Holder and FBI Director Robert Mueller headed to the White House to brief President Obama on the developments. 
 
 Secretary of State John Kerry, who is from Massachusetts, praised law enforcement for their work during "a pretty direct confrontation with evil." 
 
 "In the past few days we have seen the best and we've seen the worst of human behavior, and it's the best that all of us really want to focus on," he said. 
 
 Senate Intelligence Committee chairwoman Dianne Feinstein told NBC News it's clear the marathon bombing was "a terrorist attack." 
 
 "It's also clear, you know, that you know you don't have to be a card-carrying member of any terrorist group to commit a terrorist attack," she said. 
 
 NBC News' Jonathan Dienst and Kasie Hunt contributed to this story 
 
 Slideshow: Search for suspects in Boston Marathon bombings / A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions. Launch slideshow 
 
 Related: 
 
 Suspects to carjack victim: We are the bombers 
 
 
 
 Who are the brothers accused of the Boston Marathon bombing? 
 
 An empty metropolis: Photos show deserted streets of Boston 
 
 What we know: Timeline of terror hunt 
 
 ‘Dedicated officer’ gunned down by Boston Marathon suspects at MIT 
 
 Slideshow: Bombings at Boston Marathon 
 
 Boston bombing spurs Senate debate on tighter immigration screening 
 
 Photos from Bostonians locked down amid terror hunt 
 
 Tweeting police chatter creates confusion over Boston suspect 
 
 This story was originally published on ||||| Story highlights 58 people remain hospitalized from Monday's bombings, according to a CNN tally 
 
 "CAPTURED!!! The hunt is over" police tweet after second suspect is in custody 
 
 Investigators find ''significant amount of homemade explosives,'' a police official says 
 
 Slain suspect was wearing explosives when he died, source tells CNN 
 
 The second suspect in the Boston Marathon bombings was taken into custody Friday night, bringing to an end a massive manhunt in the tense Massachusetts capital worried by warnings the man was possibly armed with explosives. 
 
 After announcing the arrest on Twitter, Boston police tweeted: "CAPTURED!!! The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody." 
 
 Authorities confirmed the man in custody is 19-year-old Dzhokar Tsarnaev, who escaped an overnight shootout with police that left his older brother Tamerlan Tsarnaev -- the other man wanted in the bombings -- dead. 
 
 The younger Tsarnaev was in serious condition, Boston Police Commissioner Ed Davis said at a news conference. He was being treated at Boston's Beth Israel Deaconess Medical Center, hospital spokeswoman Kelly Lawman said. 
 
 Tsarnaev was cornered late Friday as he was hiding on a boat in a backyard of Watertown, a suburb of Boston. 
 
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 Police were alerted to his whereabouts by a man who went outside after authorities lifted an order for residents to stay inside during the manhunt. The resident saw blood on a boat in the backyard, Davis said. He then lifted up the tarp covering the boat and "saw a man covered with blood," he said. 
 
 It was that call that resulted in an arrest less than a week after two bombs exploded near the finish line of the Boston Marathon, shocking the nation and leaving a city on edge. 
 
 "There was an exchange of gunfire, and I don't know if he was struck," Davis said of the suspect. 
 
 Authorities, using a bullhorn, had called on the suspect to surrender: "Come out with your hands up." 
 
 Tsarnaev, according to authorities, refused to surrender. 
 
 "We used a robot to pull the tarp off the boat," David Procopio of the Massachusetts State Police said. "We were also watching him with a thermal imaging camera in our helicopter. He was weakened by blood loss -- injured last night most likely," 
 
 Tsarnaev was taken into custody after authorities rushed the boat, Davis said. 
 
 Closing a chapter 
 
 The standoff and subsequent arrest came just minutes after authorities indicated during a news conference that a manhunt for the suspect appeared to come up empty. 
 
 Authorities had cast a wide net for the suspect, virtually shutting down Boston and its surroundings after a violent night in which authorities say the brothers allegedly hurled explosives at pursuers, after killing Massachusetts Institute of Technology police Officer Sean Collier and hijacking a car. 
 
 "We've closed an important chapter in this tragedy," President Barack Obama said in a televised address. Even so, he vowed to seek answers to the motive in the attack and find out whether the suspects received any help to carry out their plot. 
 
 The government is invoking the public safety exception to question Tsarnaev, meaning in cases of national security a person can be questioned without being read their Miranda rights, a Justice Department official told CNN on condition of anonymity. The official is not authorized to publicly discuss the matter. 
 
 U.S. Attorney Carmen Ortiz told reporters the "government has that opportunity right now" to invoke the public safety exemption but stopped short of declaring it would take that step, saying only the suspect was in the hospital. 
 
 Republican Senators John McCain and Lindsey Graham called for Tsarnaev to be held as an enemy combatant. 
 
 'Glad it's over' 
 
 Word of the arrest spread quickly in suburban Watertown, where residents took to the streets to cheer the news that suspect had been arrested. 
 
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 "Thank you. Thank you. It was our pleasure," members of the Boston SWAT team said over a loudspeaker. 
 
 Mary Sullivan was walking her black Labrador earlier Friday night when gunshots rang out in her neighborhood. 
 
 "I'm glad it's over," she said. "The city and the people have gone through so much pain over these irrational decisions of these young men." 
 
 Bombing connection 
 
 The manhunt began late Thursday just hours after the FBI released photos of the two suspects in the marathon bombings. 
 
 "Investigators are recovering a significant amount of homemade explosives" from the scene of the shootout, Procopio told CNN. 
 
 It was not immediately clear what explosives were recovered, but the discovery followed a tense night in which authorities say the brothers allegedly hurled a homemade grenade and five pipe bombs at pursuers after killing an officer and hijacking a car. 
 
 Tamerlan Tsarnaev, 26, was wearing explosives and a triggering device when he died, a source briefed on the investigation told CNN on condition of anonymity. 
 
 The manhunt brought Boston to a near standstill. The Boston Red Sox announced they were postponing Friday night's game against the Kansas City Royals "to support efforts of law enforcement officers." NHL's Boston Bruins also postponed its game against the Pittsburgh Penguins. 
 
 The city's subway, bus, Amtrak train and Greyhound and regional Bolt Bus services were shut down. Taxi service across the city also was suspended for a time during the manhunt. Every Boston area school was closed. 
 
 Boston's public transit authority sent city buses to Watertown to evacuate residents while bomb experts combed the surroundings for possible explosives. 
 
 Initially, authorities said the brothers started their rampage by robbing a convenience store. By late Friday, the Middlesex District Attorney's office backtracked on the allegation, saying an investigation determined that the robbery at a 7-Eleven was unrelated. 
 
 Officer killed 
 
 The violent hours leading up to the capture began in Cambridge, across the Charles River from Boston, MIT officer Collier was shot and killed while he sat in his car on Thursday night, the Suffolk County District Attorney's Office said in a statement. 
 
 The two suspects, according to authorities, then hijacked a vehicle at gunpoint in Cambridge, telling the driver that they were the marathon bombers, a law enforcement source told CNN. 
 
 At some point, apparently at a gas station, that source said, the driver escaped. 
 
 Police, who were tracking the vehicle using its built-in GPS system, picked up the chase in Watertown. The pursuit went into a residential neighborhood, with the suspects throwing explosives at police. 
 
 A shootout erupted and ultimately one bomber -- later identified as Tamerlan Tsarnaev -- got out of the car. Police shot him, and his brother ran over him as he drove away, according to the law enforcement source, who spoke on condition of anonymity. 
 
 Richard H. Donohue Jr., 33, a three-year veteran of the transit system police force, was shot and wounded in the incident and taken to a hospital, a transit police spokesman said Friday. The officer's condition was not immediately known. 
 
 Another 15 police officers were treated for minor injuries sustained during the explosions and shootout, Jennifer Kovalich, a spokeswoman for St. Elizabeth's Medical Center, said. 
 
 Suspects background 
 
 Police believe the brothers are the same men pictured in images released Thursday by the FBI as suspects in the marathon bombing that killed three people and wounded dozens on Monday. 
 
 At least 58 people remained hospitalized, including three in critical condition, according to a CNN count. 
 
 The men are shown in the images walking together near the marathon finish line. 
 
 The first suspect -- apparently Tamerlan Tsarnaev, according to authorities -- appears in the images wearing a dark hat, sunglasses and a backpack. The second suspect, wearing a white cap, police said, is the one who remained at large throughout Friday until he was taken into custody Friday night. 
 
 But the mother of the Tsarnaev brothers refused to believe they were involved in the marathon bombings and subsequent shootout. 
 
 "It's impossible for them to do such things. I am really telling you that this is a setup," Zubeidat Tsarnaeva told state-run Russia Today from Dagestan. 
 
 "My son would never keep it in secret. ...If there is anyone who would know it would be me. He wouldn't hide it. But there was never a word." 
 
 The brothers came from the Russian Caucasus region and moved to Kazakhstan at a young age before coming to the United States several years ago. 
 
 "My youngest was raised from 8 years in America. My oldest was really properly raised in our house. Nobody talked about terrorism," their mother said. 
 
 The suspects' parents recently returned to Dagestan in the Caucasus region after living in the United States for about 10 years because they were "nostalgic," the father, Anzor Tsarnaev, told Russian state-run Zvezda TV. 
 
 He accused someone of framing his sons. "I don't know who exactly did it. But someone did." 
 
 A federal official told CNN that Dzhokar Tsarnaev came to the U.S. as a tourist with his family in the early 2000s and later asked for asylum. He became a naturalized U.S. citizen in 2012. Tamerlan Tsarnaev was not a naturalized citizen, said the official, who spoke on condition of anonymity. He came "a few years later" and was lawfully in the United States as a green-card holder. 
 
 Tamerlan Tsarnaev had studied at Bunker Hill Community College and wanted to become an engineer, according to those who knew him. He then took a year off to train as a boxer. 
 
 'I don't understand them' 
 
 The official said that a posting on a social media site in the elder brother's name included the comments: "I don't have a single American friend. I don't understand them." 
 
 Dzhokar Tsarnaev attended Cambridge Rindge & Latin, a public high school, said Eric Mercado, who graduated a year behind the suspect. Mercado said Tsarnaev had worked at Harvard University as a lifeguard. 
 
 "We hung out; we partied; we were good high school friends," Mercado told CNN. 
 
 "We're all, like, in shock. We don't really understand. There were no telltale signs of any kind of malicious behavior from Dzhokar. It's all coming as a shock, really." 
 
 Mercado said he lived a block away from the suspect and did not know his older brother. 
 
 Dzhokar Tsarnaev is currently registered as a student at University of Massachusetts Dartmouth, which ordered its campus evacuated on Friday. The school is located 65 miles south of Cambridge, just west of New Bedford. 
 
 Larry Aaronson, Dzhokar Tsarnaev's neighbor and a former teacher at the high school Tsarnaev attended, called him a "wonderful kid." 
 
 "He was so grateful to be here, he was compassionate, he was caring, he was jovial," Aaronson told CNN. ||||| Twitter is crazy right now, as second-by-second updates stream in about the live manhunt for the second Boston Marathon bombing suspect, 19-year-old Chechnyan named Dzhokhar A. Tsarnaev, pictured above. We say “second” suspect because the first suspect, Tamerlan Tsarnaev, was “killed early Friday after he and his accomplice brother robbed a 7-Eleven, shot a police officer to death, carjacked an SUV and hurled explosives in an extraordinary firefight with law enforcement,” NBC News reports. As we’ve said again and again: no day this week is complete without tragedy, violence, and extraordinary heroism in the face of evil or, in the case of last night, all of the above. 
 
 The latest: law enforcement officials have surrounded a house in the suburb of Watertown. They have, per The Atlantic, “forced media crews to move back, clearing the area completely. Some have also shut off their live feeds, to prevent the suspect from watching police movements on TV. Many networks have also gone to delay, in case something terrible happens on live TV.” 
 
 Again, this is a story changing very rapidly and very radically. We’ll continue to update as events materialize. 
 
 
 
 Update 9:53 p.m.: Tsarnaev may not be in the aforementioned Watertown home surrounded by police. According to CNN—yes, yes, we know, boo, hiss, CNN—the 19-year-old, believed to be armed and dangerous, might be as far away as Connecticut and might be traveling in a gray Honda CRV. Licence plate is 316 ES9, so if you see something, get far away and then say something. 
 
 News outlets, bereft of actual confirmed breaking news for the moment, are tracking down every person ever with whom the brothers may have interacted. The two have been alternately described as loners and sweet kids who are well-socialized. On CNN, the younger brother’s former classmate just described him as “a walking angel” who “smokes a little weed” but is not, like, “some foreign dude.” Take note, authorities! 
 
 
 
 Update 11:06 a.m.: According to The Boston Globe, Tsarnaev has reportedly abandoned the aforementioned Honda CRV and has fled on foot. Law enforcement authorities fear, but do not know for certain, that he is wearing an explosive device. 
 
 Meanwhile, various news sources have published more fleshed-out reports about the brothers’ pre–Boston Marathon lives. “The Tsarnaevs are believed to have emigrated with their family to the United States from Chechnya in 2002 after living briefly in Makhachkala, capital of Dagestan in Russia,” The New York Times reports. The younger was an accomplished high-school wrestler; the elder, a local community college student. 
 
 Amtrak service throughout New England remains more scattershot and disrupted than usual. 
 
 
 
 Update 11:50 a.m.: The boys’ uncle—their fathers’ brother—gave a remarkable news conference to reporters camped out on his lawn. Over and over again, Ruslan Tsarni insisted that the brothers’ alleged acts of violence had nothing to do with their Chechnyan heritage or regional Russian politics. (Take note, news magazines tweeting links to long-ago profiles of Chechnyan history.) Tsarni dismissed them both as “losers” and encouraged the younger brother, the current subject of the city-wide manhunt, to turn himself in and ask for forgiveness. 
 
 Update 2:05 p.m.: The suspects did not rob a 7-Eleven store. 7-Eleven would like to make that very clear. ||||| Marathon bombing suspect Tamerlan Tsarnaev was alive and struggling with Watertown police early Friday morning, when his younger brother and alleged co-conspirator drove over him in a stolen SUV, dragging him on the pavement and apparently inflicting the fatal injuries that killed him, said Watertown Police Chief Ed Deveau in a Globe interview. 
 
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 Tsarnaev, 26, was pronounced dead early Friday morning at Beth Israel Deaconess Medical Center, after engaging police in ferocious firefight in Watertown. 
 
 His brother, Dzhokar Tsarnaev, 19, is in Beth Israel Deaconess Medical Center in serious condition. He was captured Friday night, after hiding for hours in a boat stored in a Watertown backyard. Authorities believe the brothers planted bombs made from pressure cookers at the finish line of the Boston Marathon on Monday, killing three and wounding more than 170. 
 
 The chief described the chain of events that led to Tamerlan Tsarnaev’s death, beginning late Thursday, after the brothers allegedly carjacked a man in Cambridge. The two brothers let the driver out unharmed, but the driver’s cellphone was still in his car, said Deveau. Police “pinged” the phone to determine where it was, he said, which alerted police that the suspects were in Watertown. 
 
 A local officer spotted the brothers driving in two cars, a Honda sedan and the stolen Mercedes SUV, said Deveau. The brothers stopped, jumped out and started firing on the officer, while more police rushed to the scene, he said. 
 
 “Quickly we had six Watertown police officers and two bad guys in a gunfight,” said Deveau. At least 200 shots were fired; maybe as many as 300, he said. 
 
 The shots, around 12:50 a.m., woke resident Jennings Aske, at 66 Laurel Ave. When he looked out his window he saw a green Honda Civic sedan stopped in the street, with its lights on and the driver’s side windows blown out. A husky man – apparently Tamerlan Tsarnaev—stood nearby firing a gun. 
 
 “I saw him standing there shooting at police,” Aske said. “When he fired, there was a little flash of light. I could hear the gun firing. It was terrifying.” 
 
 A police SUV came down Laurel Street, hearing west toward Dexter Ave., crashing into some trash cans on the sidewalk and into a parked car. Aske said he then saw a black Mercedes SUV drive up, also heading west toward Dexter Avenue. Then he heard two or three loud explosions, one of them large enough to shake the house. In an instant, the street “was crawling with police,” he said. 
 
 Deveau said the Tsarnaev brothers hurled something at the officers – apparently a pressure cooker bomb—and there was a tremendous explosion. Police later found the lid to a pressure cooker. “We believe it was an exact duplicate of the Boston Marathon bombs,” he said. The suspects also threw five “crude grenades” at officers; three of which exploded, he said. 
 
 One of his officers put his cruiser into gear and jumped out of it, letting it roll at the suspects to draw fire, he said. The suspects peppered the car with bullets. 
 
 After several minutes, the elder brother, Tamerlan, walked toward the officers, firing his gun until he appeared to run out of bullets, Deveau said. Officers tackled him and were trying to get handcuffs on him, when the stolen SUV came roaring at them, the younger brother at the wheel. The officers scattered and the SUV plowed over Tamerlan Tsarnaev, who was dragged briefly under the car, he said. 
 
 Dzhokar Tsarnaev abandoned the SUV almost immediately on a nearby street and fled on foot, triggering an all-day manhunt. 
 
 Meanwhile, officers at the scene treated MBTA Transit Police Officer Richard H. Donohue Jr., who had arrived on the scene and was wounded in the gunfight. 
 
 Aske continued to watch for several hours, while police searched the abandoned Civic with a robot, apparently looking for explosives. 
 
 The state medical examiner has not released an autopsy report detailing cause of death. ||||| BOSTON -- The suspected Boston Marathon bomber has begun responding to investigators in writing, a source familiar with the case said Sunday evening. 
 
 Dzhokhar Tsarnaev, 19, was in serious but stable condition at a Boston hospital, according to the FBI. He had been unable to speak due to a neck and throat injury, the source said. He was also intubated and breathing with the help of a respirator and earlier, officials had said he was not in any condition to be questioned. 
 
 It was not clear, however, whether what Tsarnaev was writing was of any value. 
 
 Authorities believe Tsarnaev may have tried to shoot himself before he was taken into custody Friday night because of the trajectory and location of the bullet wound in his neck, a source familiar with the investigation said Sunday. 
 
 The shot was fired at close range, the source said, suggesting the wound was self-inflicted. He was found hidden in a boat in a backyard in Watertown, Mass., bloody and injured. He was able to step out of the boat before being taken into custody after a brief exchange of gunfire with police and then negotiation with FBI agents, said Boston Police Commissioner Edward Davis. 
 
 As he lay on a stretcher in the back of an ambulance on the way to hospital, the suspect was mouthing curse words, either to himself or to the armed authorities standing watch in the ambulance as paramedics treated him, the source said. 
 
 Prosecutors in the case said Tsarnaev was not charged Sunday. 
 
 Asked by reporters whether charges would be filed against Tsarnaev Sunday, authorities released a statement saying, "There will be no press conference or further statement from the U.S. Attorney's Office this evening regarding the Boston Marathon attacks." 
 
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 Boston Mayor Thomas Menino said at the news conference that authorities are now convinced Tsarnaev and his brother, Tamerlan, who was killed in a shootout with police Friday morning, acted on their own in the bombing. 
 
 Davis said investigators also have found a circuit board with a wire slotted through it at the bombing scene on Boylston Street and the area had been swept clean of explosives. Menino said that area is still under the control of the FBI, but will be released to the city soon and a five-phase restoration is planned. 
 
 A source involved in the investigation said late Sunday the motorist carjacked by the two brothers as their rampage began last week said the young men stated they planned to drive to New York. The source called such a trip "extremely unlikely" given the extent of the manhunt for the suspects. That assessment was proved correct by the events that followed Friday. However, that tip prompted authorities in Connecticut to be on the lookout for the brothers. 
 
 Hundreds of FBI agents and other investigators have interviewed more than 100 people who knew the brothers, the source said. They are looking for any possible links to foreign extremists and seeking to understand how the plot developed and if anyone helped them, the source said. 
 
 He confirmed that Tamerlan Tsarnaev had video of a known jihadist on his YouTube channel, footage the source had viewed and characterized as "extremely inflammatory." 
 
 Menino had said earlier it has become clear that the older brother, Tamerlan, was the more influential, describing him as the "leader" and Dzhokhar as a "follower." 
 
 "His [older] brother read those magazines that are published on how to create bombs," Menino said. 
 
 Investigators are also tracking the brothers' online activities, phone calls and text messages, examining hundreds of pieces of evidence -- including bomb components, unexploded devices as well as the brothers' vehicles, guns, and financial records seized from various sites across Boston and surrounding suburbs, authorities said. 
 
 The blasts set off near the finish line of the marathon killed three people and injured more than 180. 
 
 Sunday morning, Davis said on the CBS News show, "Face the Nation" that the crime scene from the early Friday morning firefight in Watertown, Mass., that killed Tamerlan Tsarnaev was "littered" with unexploded improvised explosive devices. 
 
 Davis said it's his belief that the brothers were "going to attack other individuals" -- and Davis said that's based on the evidence at the scene and the firepower that the brothers had. 
 
 Two men with connections to the brothers were taken into custody Saturday in New Bedford, Mass., and eventually arrested and detained on immigration violations by Immigration and Customs Enforcement, that agency announced. 
 
 The source said those arrests were made in an abundance of caution because the men were friends and former roommates of Dzhokhar Tsarnaev and had regular contact with him. Officials want to question them at greater length about whether they knew anything about the brothers' plans or provided any help to them. 
 
 Sunday morning, Boston Cardinal Sean O'Malley implored hundreds of parishioners at a Mass at the Cathedral of the Holy Cross to forgive the suspected Boston Marathon bombers and seize on the goodwill born of the tragedy. 
 
 "We must be people of reconciliation -- not revenge," he told about 800 parishioners during a service that honored four killed in last week's marathon bombings and their aftermath. Candles lighted an altar with photos of the dead victims, including the three killed Monday in the bombing, and a police officer killed Friday in a shootout. 
 
 Speaking to reporters after the Mass, O'Malley reiterated the church's opposition to the death penalty. "Forgiveness does not mean that we do not realize the heinousness of the crime. But in our hearts, when we are unable to forgive, we make ourselves a victim of our hatred. Forgiveness is part of our obligation of disciples of the Lord." 
 
 Also Sunday, Massachusetts Gov. Deval Patrick said on NBC's "Meet the Press" that video footage clearly shows Dzhokhar Tsarnaev placing a backpack near the marathon finish line. 
 
 "It does seem to be pretty clear that this suspect took the backpack off, put it down, did not react when the first explosion went off and then moved away from the backpack in time for the second explosion," Patrick said. "It's pretty clear about his involvement and pretty chilling, frankly." 
 
 Patrick said it's hard to imagine why someone would deliberately harm "innocent men, women and children in the way that these two fellows did." 
 
 The FBI had disclosed this week that it had questioned Tamerlan Tsarnaev in 2011 regarding possible terrorist connections, but found nothing and took no action against him. 
 
 Sen. Charles Schumer (D-N.Y.) said Sunday he understood that the FBI didn't find any troubling evidence during its initial contact with the suspect in 2011 -- prompted by concerns passed along by Russian authorities -- but he noted that was before Tamerlan Tsarnaev made a suspicious overseas trip. 
 
 "Then he went to Russia and he came back and almost immediately put very radical things on his website," Schumer said of the elder Boston bombing suspect. "Why didn't the FBI, having known that he was someone a foreign government at least thought might be dangerous, go interview him again?" 
 
 Schumer, speaking during an unrelated news conference, said that the federal death penalty law he helped co-author in the 1990s would be "appropriate" in the case of surviving suspect Dzhokhar Tsarnaev. 
 
 On Saturday, Rep. Peter King (R-Seaford) had also questioned the FBI's actions. 
 
 Meanwhile, rebels in Russia's North Caucasus region denied any link to the April 15 attack on the Boston Marathon in a statement posted on the vdagestan.com website. 
 
 "The Caucasian Mujahedeen are not fighting with the United States of America," according to the statement, which was attributed to unidentified Mujahedeen commanders in Dagestan. "We are at war with Russia, which is responsible not only for the occupation of the Caucasus, but also for heinous crimes against Muslims." 
 
 An FBI-led probe is looking into a six-month trip suspect Tamerlan Tsarnaev, an immigrant of Chechen descent, took around two years ago to Chechnya and neighboring Dagestan, both regions of Russia that have been embroiled in Islamist separatist movements. 
 
 In Medford, Mass., relatives and friends were expected to attend a viewing Sunday for marathon bombing victim Krystle Campbell, 29, at the Dello Russo Funeral Home, 306 Main St. from 3 to 7 p.m. On Monday at 10 a.m., there will be a procession from the funeral home to St. Joseph Church for a Mass of Christian Burial at 11 a.m. Services will conclude with burial at Oak Grove Cemetery. 
 
 The Associated Press reported that doctors said the Boston transit police officer wounded in a shootout with the bombing suspects had lost nearly all his blood and his heart had stopped from a single gunshot wound that severed three major blood vessels in his right thigh. 
 
 Surgeons at Mount Auburn Hospital in Cambridge say Richard Donohue, 33, is in stable but critical condition. He is sedated and on a breathing machine but opened his eyes, moved his hands and feet, and squeezed his wife's hand Sunday. 
 
 Emergency workers started CPR on the scene to restart his heart. Doctors say he is expected to make a full recovery and that nerves and muscles in his leg are intact. 
 
 Transit officials say Donohue had gotten out of his cruiser and was shooting at the suspects when he was hit late Thursday night in a gun battle in Cambridge. 
 
 "He went in there and engaged people who were shooting at his fellow officers," Donohue's brother, Edward, said at a news conference Sunday at the hospital. "I cannot describe the pride I have," said the younger Donohue, who is a patrolman for the Winchester Police Department. 
 
 The fellow officers included a friend, MIT police officer Sean Collier, who authorities say was shot to death at the beginning of the brothers' rampage earlier in the night. 
 
 Richard Donohue has been a transit officer for three years, said Paul MacMillan, chief of the Massachusetts Bay Transportation Authority. 
 
 The University of Massachusetts-Dartmouth, where Dzhokhar Tsarnaev was a student, reopened Sunday at noon, university officials announced on the school's website. 
 
 With Nicole Fuller, 
 
 Paul LaRocco and 
 
 The Associated Press
– The manhunt is over. Police caught Boston bombing suspect Dzhokhar Tsarnaev tonight after finding him hiding in a boat in a Watertown backyard, reports WCVB. Tsarnaev was taken by ambulance to a hospital; the AP reports that he is in serious condition. Multiple gunshots were heard at the scene of his arrest earlier this evening, preceding a standoff of about two hours. The developments began shortly after police wrapped up a late-afternoon news conference to say the 19-year-old was still at large. NBC News spoke with a relative of the resident who found Tsarnaev, and the story is a wild one: In the relative's telling, the man was having a cigarette outside when he saw that the boat's tarp was loose; he went to fix it, saw a person and bloody clothes inside the boat, "freaked out," and called police. Helicopters used thermal imaging to confirm Tsarnaev's presence. Some other developments and revelations: “All in all, this has been a tough week, but we have seen the character of our country once more,” said President Obama after the arrest. "Tonight our nation is in debt to the people of Boston and the people of Massachusetts." Politico has more details on his comments. The FBI took two men and a woman in for questioning from a house in New Bedford, but it's not clear how serious it is. A police lieutenant says Tsarnaev may have lived in the off-campus home at some point, reports AP. Authorities lifted the "shelter in place" advisory for residents of Boston, with public transportation now open again. Dzhokhar ran over his wounded brother Tamerlan in his haste to escape last night's shootout with police, reports the Globe. Tamerlan was killed, as was one officer; another officer was wounded. One notable revision: Authorities say neither of the brothers robbed a 7-11 store in Cambridge as police previously reported. A 7-11 did get robbed, but not by them, a store exec tells USA Today. "The police or someone made a mistake. Someone was confused." Tamerlan died wearing explosives and a triggering device, CNN reports. One local auto shop owner tells the Wall Street Journal that Dzhokhar, a regular customer, came to him on Tuesday and said he needed his car "right now." The mechanic protested that the bumper and tail lights weren't on it, but Dzhokhar took it anyway. "I think he probably knew something was going to happen."