Zubeidat K. Tsarnaeva, the mother of Boston bombing suspects Dzhokar and Tamerlan Tsarnaev, suggested Friday that the FBI had been surveilling her older son for several years prior to Monday's attack.

In an interview with Russia Today Friday, Tsarnaeva said that Tamerlan Tsarnaev got involved in "religious politics" five years ago, and that the FBI had previously contacted her about her son's activities.

"He was controlled by the FBI, like for three, five years," she said. "They knew what my son was doing, they knew what actions and what sites on the Internet he was going [to], they used to come...and talk to me...they were telling me that he was really a serious leader and they were afraid of him."

"How could this happen?...They were controlling every step of him, and they are telling today that this is a terrorist attack," she added.

A spokesperson for the FBI told Business Insider Friday that the agency would be putting out a statement "shortly" regarding its previous contact with either of the Tsarnaev suspects. The spokesperson would not confirm or deny that the agency had had any previous contact.

Tsarnaeva doubled down on her statements later in the interview, insisting that her sons were innocent, and had been "set up" by the FBI:

"FBI, they were scared of my oldest son, they always told me that he's a leader...they are afraid of him because, you know, he is a leader, he talks about Islam a lot."

"They were talking to my son, and they called me officially and they told me that my son is an excellent boy and they have no problem with him," she added. "At the same time, they were telling me that...he is getting information on really extremists...sites, so they were very, very afraid of him. So that's why I think that this is a setup."

Tamerlan, 26, died Thursday night in a shootout with Boston Police. A manhunt is still underway for Tsarnaeva's younger son, Dzhoker, 19.

Watch the clip below:

UPDATE, 5:58 p.m.:

CBS News' Bob Orr reports that the FBI interviewed Tamerlan Tsarnaev two years ago about his ties to extremist groups.

From CBS' Major Garrett: