Dzhokhar and Tamerlan Tsarnaev
Suspects Tamerlan Tsarnaev, wearing a dark baseball cap, and Dzhokhar A. Tsarnaev, behind him wearing a white baseball hat, walk among those watching the Boston Marathon. (Bob Leonard / Associated Press)
Tamerlan Tsamaev, right, fights Lamar Fenner in a boxing match during the 2009 Golden Gloves National Tournament of Champions in Salt Lake City. (Glenn DePriest / Getty Images)
Dzhokhar and Tamerlan Tsarnaev, both wearing baseball caps, at the marathon 10 to 20 minutes before the bombings. (Bob Leonard / Associated Press)
Tamerlan Tsarnaev, left, fights Lamar Fenner at the 2009 Golden Gloves National Boxing Tournament in Salt Lake City. (Rick Egan / Associated Press)
Dzhokhar A. Tsarnaev, left, poses with a friend upon graduating from Cambridge Rindge and Latin High School in Cambridge, Mass. The young man at right is the nephew of Boston radio show host Robin Young. The two have talked about their connection to the suspect on WBUR radio. (Robin Young / Associated Press)
A photo released by the Boston Police Department from a convenience store security camera shows a person believed to be Dzhokar Tsarnaev, identified as ‘Suspect 2’ by the FBI. (Boston Police / EPA)
A handout photograph released by the Boston Police Department shows a person believed to be Dzhokar Tsarnaev as a child. (Boston Police / EPA)