Why did Boston brothers turn rogue?

A neighbour has captured the frightening shootout that led to the arrest of the second Boston bombing suspect

BROTHERS in arms Tamerlan and Dzhokhar Tsarnaev were living the American dream.

The masterminds behind the brutal Boston marathon bombings had escaped war-torn Chechnya and emigrated to the United States in 2002 to begin a new life.

Tamerlan, 26, a talented amateur boxer, had spoken of his desire to represent the USA in the Olympics.

Dzhokhar, 19, was a medical student at the prestigious University of Massachusetts at Dartmouth and a lifeguard at a Harvard pool.

But now one brother is dead, the other in custody.

The moment of Dzhokhar Tsarnaev's arrest after a dramatic shootout with police. Picture: via Twitter/Imgur

It is not yet known what caused the two young brothers - who came to America when they were just 15 and 8 - to turn to such violence against the nation they called home.

Just eight words helped reveal the identities of the Boston bombers, thanks to the help of hero marathon runner Jeff Bauman, who lost both of his legs in the blast.

It has been revealed the Russian FSB intelligence security service told the FBI in early 2011 about information that Tamerlan Tsarnaev, one of the brothers suspected in the Boston marathon bombings, was a follower of radical Islam, two law enforcement officials say.

They were identified by authorities and relatives as ethnic Chechens from southern Russia who had been in the US for about a decade.

According to an FBI news release issued on Friday night, a foreign government said that based on its information, Tsarnaev was a strong believer and that he had changed drastically since 2010 as he prepared to leave the US for travel to a region in that country to join unspecified underground groups.

The FBI did not name the foreign government, but the two law enforcement officials identified the FSB as the provider of the information to one of the FBI's field offices and also to FBI headquarters in Washington DC.

The two officials spoke on condition of anonymity because they were not authorised to speak on the record about the matter.

The FBI said that in response, it interviewed Tsarnaev and relatives, and did not find any domestic or foreign terrorism activity.

The FBI said it provided the results in the summer of 2011. The FBI also said that it requested but did not receive more specific or additional information from the foreign government.

The bureau added that in response to the request, it checked US government databases and other information to look for such things as derogatory telephone communications, possible use of online sites associated with the promotion of radical activity, associations with other persons of interest, travel history and plans and education history.

Dzhokhar is described by friends and neighbours as a quiet, friendly, responsible and "a normal American kid," who liked sports, skateboarding and rap music.

Dzhokhar Tsarnaev, left, and Tamerlan Tsarnaev pictured in the crowd at the Boston Marathon where they are accused of planting bombs which kileld three people and injured scores more.

Tamerlan - recently married with young daughter - life took a different path as he grew older. He became a more devout Muslim praying up to five times a day.

And last night Tamerlan was dead after a shoot out with police.

Dzhokhar was in hospital in critical condition after being found hiding out on a boat in the backyard of a home in Watertown.

The pair are alleged to have been responsible for the Boston marathon bombings that killed three and left almost 200 injured - many who had limbs blown off.

Dzhokhar Tsarnaev was captured after a dramatic manhunt in Boston. His brother, Tamerlan, was killed during a violent police chase. The two ethnic Chechen brothers came from Dagestan, a Russian republic bordering the province of Chechnya. (AP Photo/vk.com)

They allegedly packed pressure cooker bombs full with nails and ball bearings to cause maximum damage.

The men are also alleged to have killed MIT campus police officer, Sean Collier, "in cold blood" as they tried to evade a massive manhunt.

The Tsarnaevs came with their family to the United States in 2002 from Kyrgyzstan, after living briefly in the Dagestan region of Russia.

They settled into their new life as well as any new immigrant would. Both were US citizens and had outwardly been fond of their new country.

Tamerlan Tsamaev after a bout against Lamar Fenner at the 2009 Golden Gloves National Tournament in Salt Lake City, Utah. Getty images.

But within the ordinariness, there were also signs of alienation.

"I don't have a single American friend," Tamerlan said in a photo essay about his love of boxing.

"I don't understand them."

Dzhokhar was a 9/11 denier who had been seen "relaxed" at a party on the Wednesday night after the bombings.

Boston bombing suspect Dzhokhar Tsarnaev posted links to Islamic websites on what appears to be his page on a Russian language social networking site. Lily Grimes reports.

Known as Jahar, his Twitter profile contained posts of hip-hop lyrics, talks about his love for TV show Breaking Bad and chats to college friends.

Dzhokhar's actions shocked many of those who had called him their friend.

He had a loyal group of allies, who yesterday were still saying they would testify for him.

Dzhokhar was an all-star wrestler and a member of the class of 2011 at Cambridge Rindge & Latin School, and won a $2500 Cambridge City Scholarship that year.

Boston Marathon bomb victim Martin Richard, 8. Picture: AP Photo/Bill Richard

"This is nothing we would ever expect, ever," said one high school friend, the nephew of Boston radio host Robin Young, who was identified on WBUR, the Boston National Public Radio station, only by the letter "Z."

"He was a laid-back kid you could always count on just to hang out with and really de-stress with," the friend said of Dzhokhar.

"There was never a sign of anything out of the ordinary."

Tamerlan was listed as a competitor in a National Golden Gloves competition in 2009.

Boston Marathon bomb victim Krystle Campbell, 29. Picture: AP

He told the Lowell Sun newspaper in a 2004 interview after winning his first fight that he liked "the USA."

He told Boston University student Johannes Hirn, who profiled him in a photo essay that if he were to become a naturalised American and chosen for the US Olympic team, "he'd rather compete for the United States than for Russia," unless his native Chechnya became independent.

Tamerlan had studied accounting at Bunker Hill Community College. He recently posted YouTube videos indicating interest in radicalised Muslim ideologies. But he had dropped out of college and increasingly become more interested in his religion.

The North Caucasus region of Chechnya that the two escaped from with their families has been ravaged by two back-to-back wars since 1994 between Russia's army and increasingly Islamist-leaning separatist rebels, and the mountainous region still sees occasional fighting.

Boston Marathon bomb victim Lingzi Lu . (AP Photo/Meixu Lu)

There was evidence that Tamerlan was a corrosive influence on his younger brother.

Zaur Tsarnaev, who identified himself as a 26-year-old cousin of the brothers, told the Boston Globe in a phone interview from Makhachkala, in southern Russia, that he had warned Dzhokhar that Tamerlan "was up to no good."

He said the older brother "was always getting into trouble. He was never happy, never cheering, never smiling. He used to strike his girlfriend. He hurt her a few times. He was not a nice man. I don't like to speak about him. He caused problems for my family."

An uncle of the two men, Ruslan Tsarni, said yesterday his nephews had shamed the family name as well as Chechnya, where the family has roots.

Speaking from his home in Makhachkala in Russia's south, the father of the Tsarnaev brothers suspected of carrying out the Boston Marathon attack says his children were framed. Deborah Gembara reports.

"Somebody radicalised them, but it's not my brother, who just moved back to Russia, who spent his life bringing bread to their table, fixing cars," he said.

"I've not been in touch with my brother."

Mr Tsarni said he had not seen his nephews since December 2005. But he said he had never heard the two associated with any violence.

"I teach my children, and that is what I feel myself. . I respect this country and I love this country. This country which gives a chance to everybody else to be treated as a human being and to be a human being . that's what I feel about this country," he said.

Maret Tsarnaev, the aunt of the Boston suspects says they couldn't have done this