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What does Russia know about Tamerlan Tsarnaev?

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There are growing questions as to whether or not U.S. intelligence officials have done more when investigating Tamerlan Tsarnaev prior to the Boston bombing.  Russia had asked the FBI to find information about him, then later asked the CIA. Both times, the U.S. said nothing had been found, but his name ended up in the master terrorism database. NBC’s Pete Williams reports.