article_snippet: Tsarnaev, 21, faces 30 charges in connection with twin bombings at the finish line of Boston Marathon April 15, 2013.
article_snippet: Three people were killed and more than 260 were injured.
article_snippet: He is also charged in the killing of a Massachusetts Institute of Technology police officer days after the bombings.
article_snippet: If the jury convicts Tsarnaev, the trial of Boston bombing suspect will move on to a second phase to determine He punishment.
article_snippet: Tsarnaev's attorneys on Monday described 26-year-old Tamerlan, who died following a gun battle with police three days after the bombing, as the driving force behind the attack, saying that his younger brother participated out of submissiveness.
highlights_snippet: Tsarnaev, 21, faces 30 charges in connection with twin bombings at the finish line of the marathon April 15, 2013 .