Russia recorded a conversation between Boston Marathon bombing suspect Tamerlan Tsarnaev and his mother, Zubeidat Tsarnaeva, "vaguely discussing" the concept of Jihad. The conversation did not mention any specific attack on the U.S., but did discuss the possibility of Tamerlan traveling to Palestine to get involved with militant groups.
This recorded call is perhaps what led Russia to ask U.S. authorities to investigate Tamerlan, who was living in the United States at the time. The FBI asked Russia for more information, but never heard back. In 2011, the Russians again requested an investigation, but still provided no further information to the FBI.