They dressed like typical American teenagers, enjoyed playing sports and tried to accommodate themselves in the US after arriving here with their family from southern Russian province of Dagestan.
Tamerlan, 26, who dreamed of winning an Olympic boxing medal and appeared to have become a more observant Muslim in the recent days, was killed in a shootout with the police on Thursday night. Dzhokhar, 19, was captured by the police in a seriously injured condition on Friday night after a massive manhunt operation that virtually closed down Boston.
US officials said they said they were unaware of any information in government databases that would have marked the Tsarnaev brothers as militants who might become involved in deadly attacks.
On Friday, the FBI said that it interviewed Tamerlan two years ago at the request of an unidentified government, the report said. The FBI's dealings with the elder brother did not produce any "derogatory" information and the matter was put to rest, a US law official said.
It was the first revelation that the Tsarnaev brothers were known to the US security officials prior to the Boston bombings.
The brothers, who have two sisters, are ethnic Chechen and and came from a predominantly Muslim region where separatists had fought two wars in the 1990s after the fall of the erstwhile Soviet Union.
Their aunt Maret Tsarnaeva, a resident of Toronto, who said the family had a refugee status in the US. Dzhokhar had arrived in the USA with his parents in 2002. His parents later returned to Dagestan.
Ruslan Tsarni, the brothers' uncle, said the had not spoken to them since 2009. Tsarni, a resident of Maryland, said Dzhokhar had not only put the family but also the entire Chechen community to shame.
Their father, Anzor Tsarnaev, however, said that both his sons had been framed and slammed the authorities for shooting Tamerlan dead.