The family of Dzhokhar and Tamerlan Tsarnaev vehemently disagree over the possibility of their relatives' role in the Boston Marathon bombings.

Dzhokhar was detained Friday night after a lengthy manhunt. His brother, 26-year-old Tamerlan, died earlier following a shootout with police after a carjacking and robbery.

After U.S. authorities identified the brothers as primary suspects in Monday's bombings, a conflicting portrait began to emerge of two young men who appeared to fit into their American lives, but experts say social isolation in an unfamiliar culture may have led them to turn to radical Islam.

Family members are unsure what to believe. Some are demanding evidence that the two men they claim are not highly religious were involved in the attack. Others are denouncing the pair, saying they brought shame to the family name.

From Chechnya to U.S.

The brothers and their extended family are ethnic Chechens. Chechnya has been plagued by an Islamic insurgency stemming from separatist wars.

Records of their birthplaces have not been confirmed, but their father, Anzor Tsarnaev, says Tamerlan was born in Chechnya and Dzhokhar in Kyrgyzstan, after the family fled war-torn Chechnya in the early 1990s.

The parents and their youngest son moved to the U.S. in 2002, his sister Maret Tsarnaeva told CBC News. The family applied for and was granted refugee status several months later. Tamerlan and his two sisters joined the family in the States the following year.

Both sisters now have children and still live in the States.

The New York Times spoke with a U.S. official who confirmed the aunt's timeline. The official added that Dzhokhar and his parents became U.S. citizens last September. Tamerlan was in the process of becoming a U.S. citizen.

Anzor moved back to the Russian republic of Dagestan some time ago when he became ill.

Tamerlan

During his time in the U.S., Tamerlan aspired to be an Olympic boxer, according to a photo gallery webpage depicting his athletic journey by photographer Johannes Hirn. Hirn's gallery has since been taken down.

Tamerlan took a semester off from engineering studies at Bunker Hill Community College. Some say it was to pursue his boxing dream, although the Wall Street Journal reports a family friend saying Tamerlan actually dropped out of college "and was soon drawn into religious matters."

ii-bomb-tamerlan-rtxyrpt

A handout photo released by the FBI shows a man believed to be Tamerlan Tsarnaev, a suspect in the Boston Marathon bombing who was killed following a police shootout. (FBI/Reuters)

Tamerlan reportedly wanted to box for Chechnya, if the nation he seemed to consider his home ever gained its independance, according to the gallery. Until then, he hoped to box for America.

According to photo captions in the gallery, Tamerlan said he would prefer to wear U.S. colours over Russian ones at any future Olympics.

Other photo captions reveal a portrait of an isolated young man who says he is a very religious Muslim and follows God's word by no longer smoking or drinking. While photos showed him boxing with his shirt off, he claimed not to take it off frequently so as not to tempt women.

Some reports claim police arrested Tamerlan in 2009 for battery after he allegedly assaulted his girlfriend.

Some photos in the online gallery show a woman believed to be his girlfriend. She is identified as a half-Portuguese and half-Italian woman who has converted to Islam.

The boys' aunt lives in Toronto and spoke to CBC News. She says Tamerlan was a stay-at-home dad and dropped out of college to take care of his two-year-old daughter. His Christian wife — it is unclear if this is the same woman described as his girlfriend in the boxing photos — worked outside the home while Tamerlan cared for the toddler, she said.

Isolation to radicalization

Tamerlan may have felt isolated from American culture.

"I don't have a single American friend," Tamerlan was quoted as saying on the photo-gallery site. "I don't understand them."

At this point, Tamerlan had apparently been living in the U.S. for at least five years.

When people are uprooted from tradition-driven patriarchal societies such as can be found in Russia's Caucusus, "they have a difficult time of not only connecting with people who do not belong to their culture, but also viewing them as human beings," Leonid Trofimov, a Russian history expert currently teaching at Bentley University in Waltham, Mass., told CBC News.

"They just don't view them the same way as those who belong to their clan," he said.

Jean-François Ratelle, a post-doctoral researcher at George Washington University and an expert in Chechen radicalism,  lived in the Republic of Dagestan with radical Islamists for three months as part of his research.

He said the brothers seemed to be not well integrated into American society, especially Tamerlan. Often, he said, young people turn to radical Islam to find answers or a society and peer network that accepts them.

The brothers were probably not radicalized directly by al-Qaeda members, he said. Rather, they probably had an indirect radicalization through internet searches about radical Islam.

In 2004, Tamerlan did not appear to have negative views about American society. In a U.S. news article, someone identified as Tamerlan said, "I like the U.S.A."

"America has lots 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 of Lowell, Mass.

Dzhokhar

The younger brother, Dzhokhar, is a second-year medical student, according to his father. But this couldn't be verified as the University of Massachusetts-Dartmouth, where Dzhokar is a registered student, is closed and in the process of a police-run evacuation.

Dzhokhar attended an elementary school in Makhackala, the capital city of Dagestan, Russia, from 1999-2001. After moving to the U.S., he attended Boston's Cambridge Ringe & Latin School, graduating in 2011.

His classmates were shocked to learn of Dzhokhar's alleged involvement in Monday's deadly bombings, according to BuzzFeed. Most say he wasn't a loner.

"He was a familiar part of the community, he didn't isolate himself," said former classmate Rebecca Mazur.

Dzhokhar is listed on the school's site as a 2011 all-star for wrestling. Part-time, he worked shifts at Harvard's Blodgett pool.

Radio host Robin Young tweeted a photo of Dzhokhar attending the high school graduation with Young's nephew, calling them happy grads and referring to the developing situation as "heartbreaking."

She tweeted that Dzhokar was one of her nephew's best friends, and that her heartbroken nephew never saw this coming.

Dzhokar attended a pre-prom party held by the nephew's family, and Young called Dzhokar a "beautiful boy in tux at a prom party and elsewhere," adding that he was a popular kid and not a loner.

In 2011, Dzhokhar was one of 45 students to win a $2,500 US scholarship for seniors at the high school and others who were going on to pursue higher education.

Gawker's Adrian Chen found what appears to be Dzhokhar's Twitter account, using a Google cache search to reveal a profile picture, since removed, of Dzhokhar.

The @J_tsar account reveals what seems like an ordinary teenage boy. He engages in a Twitter debate over which TV show is better: Game of Thrones or Breaking Bad. Other tweets include him watching sports and quoting rap lyrics.

But some messages hinted at a darker side. On April 16, the day after the bombings, he responds to a private tweet with the message: "I've been looking for those, there is a shortage on the black market if you wanna make a quick buck, nuff said.."

On April 8, he wrote, "If you have the knowledge and the inspiration all that's left is to take action."

In March 2012, he tweeted, "a decade in america already, i want out."

The day after the bombings someone used the account to tweet: "I'm a stress free kind of guy." As of Friday afternoon, that was the second last tweet from the account. In the hours since Chen discovered the account, its followers have risen to almost 59,000 people.

Radical interests revealed

CBC News discovered a social networking site page believed to belong to Dzhokhar. On the VKontakte page, Dzhokhar lists Chechnya as one of his interests, as well as everything connected to the Chechen Republic.

He listed Islam as his worldview, and said his personal priorities were his career and money.

The page shows several videos that he has watched that are about Islam, such as One of the chameleon signs of Allah.

The page suggests he accessed two deleted videos, both entitled terrorists. He also liked a video with the title: Russian guys who converted to Islam.

A YouTube account believed to belong to his older brother, Tamerlan, shows similar videos.

Aberfoyle International Security director Andrew McGregor told CBC News that Tamerlan had recently become interested in apocalyptic Islamic prophecy, which he said is the Islamic equivalent of Armageddon.

Tamerlan's aunt says he was not a devout Muslim, but started praying five times a day about two years ago. She said she prefers he pray than smoke, do drugs or other "unlawful stuff."

VKontakte says the page was last visited today at 5 a.m. Dzhokhar allegedly joined the social networking site in August 2012.

'Losers' says uncle

The boys' uncle, Ruslan Tsarni, held a press conference to speak with reporters camping out on his property. He called the people responsible for the Boston Marathon bombings "losers," suggesting it may be his nephews who are responsible.

He said he had not spoken to the pair since Dec. 2005 due to a private family fight. However, yesterday, one of the men called him and reconciled.

Ruslan's brother, Alvi Tsarni, told media the nephews would send Ruslan threatening messages. Once, on the phone, one of the men tried to convince Alvi that if he was manly, he would join the men in their fight.

Tsarni offered his condolences to the victims of the bombings, and called on the surviving nephew to surrender to police and ask for forgiveness.

He said he can only think of two reasons someone could commit such an atrocitiy: "Being losers [and] hatred to those who were able to settle themselves."

Tsarni said he had no inclination the men had anti-American sentiments, and said his family is ashamed of their alleged actions.

"Of course we're ashamed. Yes, we're ashamed," he said. "They're children of my brother."

However, he stresses his brother could not be responsible for feeding them anti-American beliefs. Anzor worked tirelessly to feed his family, spending lots of his time fixing cars at mechanic shops, Tsarni said.

The Wall Street Journal reports Anzor dreamed of opening his own shop, but never mastered English and struggled working odd mechanic jobs for about $10 an hour.

'No one knows the truth,' says sister

Anzor, the father of the suspects, says that Dzhokhar is a smart and accomplished young man.

One of their sisters, Alina Tsarnaeva, reluctantly echoed this sentiment about both her brothers to reporters from The Star-Ledger of Newark. They spoke to her at her apartment while she stood behind a slightly opened door.

Alina called Dzhokhar "an amazing child" and Tamerlan "a kind and loving man."

She said she does not know if her brothers are behind Monday's bombings because "at the end of the day, no one knows the truth."

While he wants his son to give up peacefully, Anzor told ABC News that if the U.S. kills Dzhokhar, "all hell will break loose."

He said his sons called him earlier this week and reassured him they were okay.

Father, Mother believe sons were framed

An Interfax correspondent has also spoken to a man claiming to be Anzor, who said he learned about the incident from TV reports.

"My opinion is the special services have framed my children, because they are practicing Muslims. Why did they kill Tamerlan? He was supposed to be caught alive," the man said.

Zubeidat Tsarnaeva, their mother, told CNN she believed this was a setup. She said it was "impossible" her sons did this because they would never hide this type of activity from her.

Tsarnaeva also told CNN that her older son, Tamerlan, got involved in religious politics about five years ago. She told the U.S. network she believed the FBI had consulted her son.  She said the FBI knew what her son was doing and said they knew what sites on the internet he was visiting.

A federal law enforcement official said the FBI interviewed Tamerlan Tsarnaevt at the request of a foreign government in 2011 and that nothing derogatory was found, The Associated Press reported.

The FBI shared its information with the foreign government, said the official, who spoke on the condition of anonymity because they were not authorized to speak about the case publicly. The official did not say what country made the request about Tamerlan Tsarnaev, or why.

Their paternal aunt, Maret, told CBC news she believed her nephews are innocent and demanded proof of their guilt. She also believes Tamerlan is still alive.

"They have no motive for that," she said. "It's just not the case, it cannot be true."

Ratelle dismissed the family's claims of a setup as a "typical narrative" from Chechen families when faced with a shameful situation. He said Chechen society is based on honour and shame, and it can be seen as very shameful to be related to suicide bombers. So, this may be the family's coping mechanism for rejecting the shame associated with the men's actions.

All the family members who have spoken publicly seem to agree that Dzhokhar should surrender peacefully, though some say he should beg for forgiveness, while others say he should demand to see any alleged proof of his guilt.

With files from the Associated Press