One of the Boston bombing suspects set off alarm bells among his family a year ago during a trip here to visit relatives, ABC News has learned.
According to a family member, Tamerlan Tsarnaev, a devout Muslim, was kicked out of his uncle's house because of his increasingly extremist views on religion.
Tamerlan Tsarnaev, 26, and his brother Dzhokhar, 19, are believed to have placed bombs at the Boston Marathon, killing three and wounding 170. Tamerlan was killed in a shootout with police early Friday and Dzhokhar was badly wounded and captured by police Friday night.
Tamerlan Tsarnaev spent roughly six months in Russia in 2012, but the relative, who insisted on anonymity to avoid offending other family members, insisted the young man had been radicalized in the United States before his trip.
Dagestan is one of the poorest and most violent regions of Russia, home to an Islamist insurgency that seeks to establish an independent state. So far, no links have tied him to militant groups here.
Members of Congress, however, say those six months last year were a turning point in Tamerlan Tsarnaev's radicalization.
"When he came back he starting posting more radical jihadist YouTube videos and started becoming more of a fundamentalist Muslim," Rep. Michael McCaul, chairman of the House Homeland Security Committee, told ABC News Friday.
"My concern is that he may have gone over there to visit his father and he received training and then became radicalized and then came back. Something happened in that period of time. He was not like that before," McCaul said.
The FBI, meanwhile, also looked into Tamerlan Tsarnaev in 2011.
In a statement Friday, the bureau said it investigated Tsarnaev on behalf of a foreign government, though it did not reveal which one.
"The request stated that it was based on information that he was a follower of radical Islam and a strong believer, and that he had changed drastically since 2010 as he prepared to leave the United States for travel to the country's region to join unspecified underground groups," the FBI statement said.
The bureau said that in response to the request it combed through its databases and interviewed the man and members of his family, but did not find any evidence he was tied to terror groups.
"The FBI did not find any terrorism activity, domestic or foreign, and those results were provided to the foreign government in the summer of 2011. The FBI requested but did not receive more specific or additional information from the foreign government," the FBI statement said.
The family member described Tsarnaev's father and mother as good parents who are distraught at the news. They tried to evade the media today after granting several interviews a day earlier, even instructing family members to tell reporters they had left for Chechnya. The pair were briefly spotted, however, by journalists waiting outside their home.
The relative said he saw them Friday and that the mother was sobbing and the father suffered some sort of panic attack in the evening. Also on Friday, according to a security source, the parents were questioned by security services.
The relative said Tsarnaev's father is a "traditional Muslim" who eschews extremism. He couldn't imagine his son would do such a thing, the family member said.