US 'pinged' when Boston suspect flew to Russia

WASHINGTON, DC - APRIL 23: Homeland Security Secretary Janet Napolitano testifies before the Senate Judiciary Committee on Capitol Hill April 23, 2013 in Washington, DC. Napolitano answered questions from senators about the proposed immigration reform legislation and the Boston Marathon bombing suspects. Photo/CHIP SOMODEVILLA/Getty Images/AFP

What you need to know:

  • A year earlier, Tsarnaev had been questioned by the FBI at the request of Moscow, but investigators apparently concluded he was not a threat.



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