WASHINGTON - U.S. officials say Russian authorities secretly recorded a conversation in 2011 in which one of the Boston bombing suspects vaguely discussed jihad with his mother.
Officials say a second call was recorded between the suspects' mother and a man under FBI investigation living in southern Russia.
The officials spoke on condition of anonymity because they were not authorized to speak publicly about the ongoing case.
They say the Russians shared this intelligence with the U.S. in the past few days.
The conversations are significant because, had they been revealed earlier, there might have been enough evidence for the FBI to initiate a more thorough investigation of the Boston bombing suspects' family.
Meanwhile, U.S. officials said the bombing suspects' mother had been added to a federal terrorism database about 18 months before the April 15 attack - a disclosure that deepens the mystery around the Tsarnaev family and marks the first time American authorities have acknowledged that Zubeidat Tsarnaeva was under investigation before the tragedy.
Dzhokhar Tsarnaev is charged with joining with his older brother, Tamerlan Tsarnaev, now dead, in setting off the shrapnel-packed pressure-cooker bombs. The brothers are ethnic Chechens from Russia who came to the United States about a decade ago with their parents.
Investigators have said it appears the brothers were angry about the U.S. wars in Afghanistan and Iraq.
Two government officials, speaking on condition of anonymity because they were not authorized to speak publicly about the investigation, said the CIA had Zubeidat Tsarnaeva's name added to the terror database along with that of her son Tamerlan after Russia contacted the agency in 2011 with concerns that the two were religious militants.
About six months earlier, the FBI investigated mother and son, also at Russia's request, one of the officials said. The FBI found no ties to terrorism. Previously U.S. officials had said only that the FBI investigated Tamerlan Tsarnaev.
In an interview from Russia, Tsarnaeva said Friday that she has never been linked to terrorism.
"It's all lies and hypocrisy," she said from Dagestan. "I'm sick and tired of all this nonsense that they make up about me and my children. People know me as a regular person, and I've never been mixed up in any criminal intentions, especially any linked to terrorism."
Tsarnaeva faces shoplifting charges in the U.S. over the theft of more than $1,624 worth of women's clothing from a Lord & Taylor department store in Natick in 2012.