Dzhokhar Tsarnaev was taken into custody Friday evening after a manhunt that left the city virtually paralysed and his older brother and accomplice dead.
Zubeidat Tsarnaeva told the English-language Russia Today television station in a phone interview that her son Tamerlan Tsarnaev, 26, had been "controlled" by the FBI for at least three years.
"He (Tamerlan) was controlled by the FBI, like, for three to five years.
"They knew what my son was doing, they knew what sites on the Internet he was going to.