As manhunt ends, new questions emerge in Boston bombings

• Mystery surrounds the motivations of Chechen brothers
• Wounded suspect was hiding in a boat stored in backyard
• Suspect%27s capture comes after Friday morning death of brother%2C four days of hiding

The surviving suspect in the Boston Marathon bombing remained hospitalized with serious injuries this morning as the hunt for answers goes full tilt to discover why the alleged terrorists turned against a country they once embraced.

Police captured Dzhokhar Tsarnaev Friday night, ending a tense, five-day drama that gripped Massachusetts with fear and rekindled the specter of terror across the nation. He and his brother Tamerlan Tsarnaev, killed in an earlier gun battle with police, are Chechens who came to the U.S. and - for a time - seemed to want to succeed in America.

"I'm in complete shock," said Rose Schutzberg, 19, who graduated high school with Dzhokhar and now attends Barnard College in New York. "He was a very studious person. He was really popular. He wrestled. People loved him."

Dzhokhar Tsarnaev, 19, was found about 8:45 p.m. holed up in a covered boat stored in the backyard of a Watertown, Mass., residence. He was led to an ambulance and driven to a hospital, where he is listed in serious condition.

U.S. officials said a special interrogation team for high-value suspects would question him without reading him his Miranda rights, invoking a rare public safety exception triggered by the need to protect police and the public from immediate danger.

His capture came two hours after Massachusetts Gov. Deval Patrick ended a Boston-area lockdown after a massive, day-long search of suburban Watertown, which seemingly failed to flush out the teenager.

Dozens of bystanders cheered and applauded as police left the scene.

James Maserejian, 48, a jeweler who lives near the capture scene, said the arrest is just the beginning of a new phase in the search for answers. Maserejian stressed the importance that Tsarnaev should live and be made to face the victims of his crimes and their families.

"We need answers," he said. "Why did he do it? What were his causes? Why did he take innocent lives?"

The capture came quickly - and somewhat unexpectedly. Minutes after government officials lifted an order to residents of Watertown to stay in their homes, a man on the town's Franklin Street ventured outside for the first time in a day. That's when he spotted blood smeared on the boat parked in his driveway. He lifted the tarp and saw a man lying there covered in blood.

It marked the end of a manhunt that consumed Bostonians for an anxious 24 hours. But it also ushered in many questions about the suspects and how they had become radicalized, even as they lived fairly normal American lives.

Tamerlan Tsarnaev was an amateur boxer in the Boston area and his younger brother Dzhokhar was popular in high school, won a city scholarship for college and liked to hang out with Russian friends off-campus.

But their roots were in a side of the world with much more political instability than their new homeland. "Why people go to America? You know why," their father, Anzor Tsarnaev, told the Associated Press in an interview from Russia, where he lives now.

"Our political system in Russia. Chechens were persecuted in Kyrgyzstan, they were problems." The family had moved from Kyrgyzstan to Dagestan, a predominantly Muslim republic in Russia's North Caucasus that has become an epicenter of the Islamic insurgency that spilled over from Chechnya.

Tamerlan occasionally commented on a certain alienation he felt in America. "I don't have a single American friend. I don't understand them," he was quoted as saying in a photo package that appeared in a Boston University student magazine in 2010.

He identified himself then as a Muslim and said he did not drink or smoke: "God said no alcohol." He said he hoped to fight for the U.S. Olympic team and become a naturalized American.

As a boxer, he was known for his nerve. "He's a real cocky guy," said one trainer who worked with him, Kendrick Ball. He said the young man came to his first sparring session with no protective gear. "That's unheard of with boxing," Ball said. But he added: "In this sport, you've got to be sure of yourself, you know what I mean?"

More recently, Tamerlan - married, with a young daughter - became a more devout Muslim, according to his aunt, Maret Tsarnaeva. She told reporters outside her Toronto home Friday that the older brother had taken to praying five times a day.

Tamerlan attended Bunker Hill Community College in nearby Charlestown as a part-time student for three semesters from 2006 to 2008. He studied accounting.

Anzor Tsarnaev, said Dzhokhar is "a true angel" and "an intelligent boy." In subsequent media interviews, he said his sons had been framed for Monday's bombings.

Ruslan Tsarni, an uncle who had not spoken to his brother's sons since December 2005, urged Dzhokhar to turn himself in to authorities. Meeting with reporters Friday outside his home in Montgomery County, Md., Tsani said he believed the brothers may have been recently "radicalized."

Albrecht Ammon, 18, lived directly below the apartment of the two suspects. He said he recently saw Tamerlan in a pizzeria, where they argued about religion and U.S. foreign policy. He quoted Tsarnaev as saying that many U.S. wars are based on the Bible, which is used as "an excuse for invading other countries."

Dzhokhar Tsarnaev is believed to have dropped a backpack laden with explosives at the site of Monday's second explosion. He was pictured wearing a white baseball cap in video images released by the FBI Thursday.

His page on the Russian social networking site Vkontakte says he attended Cambridge Rindge and Latin School, graduating in 2011. He won a $2,500 college scholarship from the city of Cambridge. On the website, his world view is described as "Islam" and he says his personal goal is "career and money."

Larry Aaronson, a neighbor and retired history teacher at Cambridge Rindge and Latin School, got to know Dzhokhar while taking photos of the high school wrestling team and other school activities.

"It's completely out of his character," Aaronson said of Dzhokhar's alleged role in the bombings. "Everything about him was wonderful. He was completely outgoing, very engaged, he loved the school. He was grateful not to be in Chechnya."

Dzhokhar was not overtly political or religious, Aaronson says. "He spoke and acted like any other high school kid."

Aaronson says he can't reconcile the young man he knows with the characterizations he's seeing in the media. "I cannot do it," he says. "I mean this from the deepest part of my heart: It's not possible it's the same person. It's just not possible."

The younger brother was described by friends as well-adjusted and well-liked in both high school and college, though at some point in college, his academic work reportedly suffered greatly.

Dzhokhar was on the school's wrestling team. And in May 2011, his senior year, he was awarded a $2,500 scholarship from the city to pursue higher education, according to a news release at the time. That scholarship was celebrated with a reception at city hall.

The New Bedford Standard-Times reported that Dr. Brian Glyn Williams, who teaches Chechen history at the University of Massachusetts at Dartmouth, said he had tutored Dzhokhar in the subject when he was in high school.

"He was learning his Chechen identity, identifying with the diaspora and identifying with his homeland," Williams said, adding that Dzhokhar "wanted to learn more about Chechnya, who the fighters were, who the commanders were."

Dzhokhar went on to attend UMass-Dartmouth, according to university officials. He lived on the third floor of the Pine Dale dormitory. Harry Danso, who lives on the same floor, said he saw him in a dorm hallway this week.

"He was regular, he was calm," said Danso.

The school would not say what he was studying. His father said his younger son was "a second-year medical student," though he graduated high school in 2011.

Still, The New York Times reported that a university transcript revealed that he was failing many of his college classes. In two semesters in 2012 and 2013, he got seven failing grades, including F's in Principles of Modern Chemistry, Intro American Politics, and Chemistry and the Environment.

The Times also reported that Tamerlan Tsarnaev was interviewed by the FBI in 2011 when a foreign government asked the bureau to determine if he had extremist ties. The government knew that he was planning to travel there and feared that he might be a risk, the Times reported an unnamed government official as saying.

The official would not say which government made the request.

Dzokhar Tsarnaev's capture unfolded quickly Friday night. Police, who arrived on the scene immediately after receiving the resident's tip that someone was hiding in a boat on his property, exchanged fire with the man for an hour, Boston Police Commissioner Ed Davis said. In the end, it took the FBI's hostage rescue team another hour to coax Dzhokhar Tsarnaev from the boat and take him into custody.

SWAT teams had spent the day in a house by house search within a 20-block perimeter, but came up short.

"He managed to elude us by being slightly outside the perimeter we set up," he said..

Police proceeded cautiously, fearing Tsarnaev would have explosives and homemade hand grenades like he'd used when he and his brother confronted police the night before. A helicopter flying overhead trained its heat-seeking sensors on the boat to confirm someone lay under the tarp.

He had been wounded in a early Friday morning firefight with police that killed older brother, Tamerlan Tsarnaev, 26.

"We're exhausted, but we have a victory here tonight,'' said Col. Timothy Alben, State Police Superintendent.

U.S. Attorney Carmen Ortiz said charges against Tsarnaev have not yet been determined. "This is still an active, on-going investigation,'' Ortiz said, adding that it will be Attorney General Eric Holder's decision whether to seek the death penalty.

President Obama praised law enforcement.

"Tonight, our nation is in debt to the people of Boston and to the people of Massachusetts," he said at the White House.

The president said "there are still many unanswered questions" about the bombing, and the families of this week's victims deserve answers. Obama said he has directed the FBI and other agencies to get those answers.

"We will determine what happened," Obama said, including any international connections the suspects may have had.

Obama also asked Americans not to "rush to judgement" on the case, including possible motives for the bombing.

For most of the day, hundreds of police conducted a methodical, house-to-house sweep in Watertown for Tsarnaev.

Hours earlier, Tamerlan Tsarnaev died after a dramatic car chase and shootout with police during which the more than 200 rounds of ammunition were fired. As they were pursued, the brothers threw several pipe bombs and a grenade at police as they attempted to flee in a carjacked SUV.

State Police Superintendent Timothy Alben said Dzhokhar Tsarnaev later abandoned the stolen vehicle in Watertown and fled by foot.

Authorities believe there are no other accomplices in Monday's twin bombings, which killed three and wounded over 180 people near the finish line of the Marathon. Several victims lost limbs in the bombings, and some remain in critical condition at area hospitals. Investigators have not found any formal links to an international terror group.

The brothers' acts continue to befuddle authorities, family and friends. Students at the University of Massachusetts Dartmouth, where Dzhokar was a student, say they saw him on campus following Monday's bombings.

During the overnight and early-morning pursuit of the brothers, a federal official familiar with the case said authorities recovered a handful of improvised explosive devices (IEDs), including one in the possession of Tamerlan Tsarnaev. All of the devices appeared to be homemade explosives, including pipe bombs. Several were detonated by police Friday afternoon.

Police took Tamerlan Tsarnaev to Beth Israel Deaconess Medical Center following the exchange of gunfire with police at about 1:20 a.m. Friday. Dr. David Schoenfeld said medical personnel tried to revive him. He had multiple gunshot wounds and burn and gaping blast wounds that appeared to have come from an explosive device strapped to his body.

Dzhokar's escape prompted Gov. Patrick to order the city of Boston and its surrounding suburbs locked down and its residents to remain in their homes for much of Friday. The Boston Red Sox and Bruins postponed Friday night games.

Businesses in Watertown, Newton, Waltham, Belmont, Cambridge and the Alston and Brighton neighborhoods of Boston were requested to close, while residents were told to remain indoors until the suspect was caught.

Massachusetts also shut down mass transit, including buses and trains, in Boston and surrounding suburbs, Kurt Schwartz, director of Massachusetts Emergency Management Agency said.

The manhunt for the marathon bombing suspects had turned into hot pursuit late Thursday evening. MIT campus police officer Sean Collier was shot multiple times as he was sitting in his car.

Collier, 26, was later pronounced dead at Massachusetts General Hospital. He had been a campus cop since January 2012 and previously, a civilian employee at the Somerville Police Department.

The brothers carjacked a Mercedes SUV between 12:15 and 12:30 a.m, holding the driver at gunpoint for a half hour before he was shoved from the car unharmed. A federal law enforcement official, who was not authorized to comment publicly, said the men allegedly told the driver that they were the Marathon bombers.

The official said the suspects' allegedly acknowledged their roles in the Marathon bombings to both intimidate the driver and brag about the bombings.

Police found the car and the suspects in Watertown, and pursued them into a residential neighborhood where gunfire was exchanged.

A transit police officer, Richard H. Donohue Jr., 33, was shot once during the firefight. He underwent surgery and is listed in critical condition at Mount Auburn Hospital.

Alvi Tsarnaev, another uncle of the suspects, said Friday that Tamerlan phoned him Thursday night at about 7 p.m., the first time they had spoken in about two years.

"He said, 'I love you and forgive me,' " said Alvi Tsarnaev, who lives in Montgomery Village, Md. He wasn't seeking forgiveness for the bombing, but asking for forgiveness because he hadn't spoken to him in so long.

"We were not talking for a long time because there were some problems," Alvi Tsarnaev said without elaborating. "We were not happy with each other."

They spoke for about five minutes, he said. Tamerlan, who is Muslim, started out by saying, "Salam Aleikum," an Arabic greeting meaning "peace on you." He then praised his uncle for keeping up with his Muslim prayers.

"He told me he was happy," he said. "He was asking, 'Did you pay your mortgage?' I told him I was trying to pay. I asked him what he was doing. He said, 'I fix cars, I got married, got a baby.'

"Killing innocent people, I cannot forgive that," Alvi Tsarnaev said. "It's crazy. I don't believe it now even. How can I forgive this?"

The Lowell Sun reported that Tamerlan Tsarnaev was a Golden Gloves boxer who told the newspaper that "I like the USA" after winning his first fight in 2004 in Lowell. He fought in the 178-pound novice class.

According to the Sun, Tamerlan and his family moved to the USA in 2003, hoping to start a new life. "America has a lot of jobs. That's something Russia doesn't have. You have a chance to make money here if you are willing to work," he told The Sun.

Contributing: The Associated Press; John Bacon and Mary Beth Marklein in McLean, Va.; Yamiche Alcindor and Melanie Eversley in Boston, William Welch in Los Angeles, Judy Keen in Chicago and Shawn Cohen of The (Westchester County, N.Y.) Journal News.