this has been a cbs news special report. i'm nora o'donnell in boston. ♪ good morning to viewers in the west. tuesday, april 16, 2013. welcome to a special edition of "cbs this morning." terror at the boston marathon. two bombs leave three people dead. more than 140 injured and a nation in shock. john miller has the latest on the investigation. >>> h boston emotional stories emerging from people's whose lives changed in an instant. we'll talk to eyewitnesss and a doctor who is treating the injured. >>> and amid the horrific story, stories of kindness and compassion. >> we begin with today's eye opener, your world in 90