The mother of the accused Boston Marathon bombers was secretly recorded discussing jihad in a telephone conversation with her now dead-son, officials said Saturday.
The call between Zubeidat Tsarnaev and 26-year-old Tamerlan was intercepted by Russian wiretaps in early 2011.
But the information was not shared with American authorities at the time, officials said.
In a second call, also recorded by a Russian internal security service, the mother was captured talking to someone in southern Russia who is under FBI investigation in an unrelated case, officials said.
The conversations raise new questions about the warnings that the Russians sounded to American authorities about Tamerlan in 2011.
At the time, the Russians told the FBI only that they had concerns that Tamerlan and his mother were religious extremists.
The FBI conducted a limited investigation of Tamerlan, found no terror ties and closed the case in June 2011.