A blood-stained message that prosecutors say Boston Marathon bombing suspect Dzhokhar Tsarnaev wrote on the inside of a boat is seen with bullet holes. Tsarnaev, 21, is accused of killing three people and injuring 264 with a pair of homemade bombs at the race's crowded finish line on April 15, 2013, as well as fatally shooting a police officer three days later. REUTERS/U.S. Department of Justice/Handout via Reuters
Federal prosecutors contend Dzhokhar Tsarnaev, who emigrated from Chechnya, was driven by an extremist view of Islam and a desire to strike back at the United States in revenge for military campaigns in Muslim-dominated countries.