Bomb ` ` tore large chunks of flesh out '' of ` 's body , prosecutor says . ` admits ` Tsarnaev 's role in Boston suicide bombings . Older ` influenced him to kill him , prosecutor says .
Bomb `` tore large chunks of flesh out '' of boy 's body , prosecutor says . Defense admits Dzhokhar Tsarnaev 's role in Boston Marathon bombings . Older brother influenced Tsarnaev to follow him , attorney says .