A third person has died from the bombing , Boston Police Commissioner Ed Davis says . An 8-year-old boy was one of those killed . The bombs were small , with no initial sign of high-grade explosive material , an official tells CNN . Comment:
A third person has died from the bombing , Boston Police Commissioner Ed Davis says . An 8-year-old boy was one of those killed . The bombs were small , with no initial sign of high-grade explosive material , an official tells CNN . Obama vows those guilty `` will feel the full weight of justice ''