One of the two ethnic Chechens suspected by U.S. officials of being behind the Boston Marathon bombings had been under FBI surveillance for at least three years, his mother said. Zubeidat Tsarnaeva told the English-language Russia Today state television station in a phone interview, a recording of which was obtained by Reuters, that she believed her sons were innocent and had been framed. Tamerlan Tsarnaev, 26, was killed in a shootout with police and his 19-year-old brother Dzhokhar was captured after a day-long manhunt. He (Tamerlan) was controlled by the FBI, like, for three to five years," she said, speaking in English. "They knew what my son was doing, they knew what sites on the Internet he was going to," she said. Tsarnaeva echoed the boys' father, Anzor, who said ... that he believed they had been framed. Tsarnaeva suggested FBI officers had visited her home when she still lived in the United States and told her that Tamerlan "was really an extremist leader and that they were afraid of him. It is really, really a hard thing to hear. And being a mother, what I can say is that I am really sure, I am, like, 100 percent sure, that this is a set-up," she said. U.S. government officials have said the brothers were not under surveillance as possible militants. But the FBI said in a statement on Friday that in 2011 it interviewed Tamerlan at the request of a foreign government, which it did not identify. The FBI statement was the first evidence that the family had come to security officials' attention after they emigrated to the United States from Dagestan about a decade ago.