The Last Word with Lawrence O'Donnell 04/29/13

Female DNA found on Boston bomb

NBC's Pete Williams reports the latest in the Boston bombings cases, including female DNA found on at least one bombs used in the attacks. MSNBC's Alex Wagner talks with NBC's national investigative correspondent, Michael Isikoff, about the importance of this new information and any leads on how the two bombing suspects may have been radicalized. ... more Duration: {{video.duration.momentjs}}