Former FBI agent: All phone calls recorded, no digital communication secure

Last week, the press focused on Katherine Russell, the widow of Boston bombing suspect Tamarlan Tsarnaev, as officials have been trying to determine what she knew about the bombing.

After investigators found "al-Qaeda's Inspire magazine and other radical Islamist material on her computer," they focused on phone calls between Russell and her husband to determine if she participated in the plot.

On the night the FBI released the surveillance picture of him, she talked to Tsarnaev on the phone. CNN Out Front host Erin Burnett questioned Tim Clemente, former FBI counterterrorism agent, about the government's surveillance capabilities.