Possible Major Break In Boston Marathon Bombings

Possible Major Break In Boston Marathon Bombings
Officials congregate near the blast site of the Boston Marathon explosions, Thursday, April 18, 2013, in Boston. The city continues to cope following Monday's explosions near the finish line of the marathon. (AP Photo/Julio Cortez)

We are following what could be a major break in the Boston Marathon bombings. Investigators may have a gotten a clear look at the people responsible. ABC News Crime & Terrorism Analyst Brad Garrett has more.