he helped the fbi identify tamerlan tsarnaev dzhokhar's older brother. new video reveals the horror the images described in emotional detail by the people who lived through it. >> that's my sister. this is my brother. >> reporter: inside the courtroom, jurors and others could be seen fighting back tears. tsarnaev sat slouched in his seat, rarely turning to make eye contact with the witnesses he's accused of trying to kill. the prosecution is moving very quickly through their witnesses. tsarnaev's lawyers have barely cross-examined any of them. they have already acknowledged that it was him that zaedzhokhar tsarnaev should be held for the death and destruction. had their goal is to try to spare him from the death penalty. deborah feyerick, boston. >> as deborah reported the trial isn't about guilt or innocence but whether tsarnaev should live or die.