Intelligence experts in Washington are paying close attention to new details about the brothers suspected in the Boston bombings.
The two reportedly have been in the country for the past decade, most recently living together in Cambridge, Massachusetts.
The older, now deceased brother was a competitive boxer who spent six months in Russia last year.
Former Secret Service Agent Dan Bongino says that trip could be key to linking the two to a radical group.
"Who were their mentors who taught them how to do this?" he asks.
Earlier Friday the FBI blocked off a Maryland neighborhood street and interviewed the suspects' uncle at his home.
"I say, Jahar, if you are alive turn yourself in and ask for forgiveness," Ruslin Tsarni pleaded.
Tsarni expressed shock and accused his nephews of shaming the family.
"I say what I think was behind it, being losers and not being able to settle themselves and hating everyone within," he said of the pair.
At the White House President Obama met with more than a dozen members of his national security team, including the FBI Director.
Secretary of State John Kerry said the country is in "direct confrontation with evil".
"In the past few days we've seen the best and the worst of human behavior, and it's the best all of us want to focus on," Kerry added.
Homeland Security Secretary Janet Napolitano was scheduled to testify about immigration reform on Capitol Hill Friday, but had to cancel to focus on the Boston investigation.
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