bombs at the boston marathon. the tsarnaev brothers set off two bombs in a terror attack. tamerlan was killed by police his younger brother remains in custody charged with murder. his trial is suspected to gipp in november with us a man directly affected by the terror attack. jeff bowman who lost both of his legs. author of the brand new book called "stronger" which goes on sale today. you identified tam merlin the older brother, how did you do that? >> first, i was in the ambulance, and i was kind of not worrying about my life anymore and i kind of thought i was going to make it so i started to think what happened. that guy looks suspicious. i knew it was a bomb. and he just looked very suspicious i were standing