Defense rests in death-penalty phase of Boston bombing trial

A federal jury last month found Tsarnaev, 21, guilty of killing three people and injuring 264 with a pair of homemade pressure-cooker bombs at the race's crowded finish line as well as fatally shooting a police officer three days later.

Defense attorneys argued that Tsarnaev's 26-year-old brother, Tamerlan, who died hours after the shooting, was the driving force behind the attack with Dzhokhar playing a secondary role. (Reporting by Scott Malone; Editing by Meredith Mazzilli)