The crowd on Boylston Street outside the Forum restaurant about 90 minutes before the explosions. (Photo courtesy: Sharona Dayan)
Boston Marathon Bombings Evidence
This photograph, taken from a surveillance camera, shows one of the suspects of the Boston Marathon bombing standing near 8-year-old Martin Richard, who was killed in one of the blasts. The circle at bottom right appears to be a backpack or a package. (Image credit: Daily Mail-WBZ-TV)
Boston Marathon Bombing Suspects
Investigators say this is Dzhokhar and Tamerlan Tsarnaev at the bombing site. (Photo courtesy: Bob Leonard)
Boston Marathon Bombing Suspects
Several of Bob Leonard's Boston Marathon photos captured the bombing suspects. (Photo courtesy: Bob Leonard)
Boston Marathon Bombings Suspects
The FBI released this April 15, 2013 surveillance image of the 2 suspected bombers on Boylston Street, April 18, 2013. (Image courtesy: FBI)
Tsarnaevs-Surveillance
The FBI released this April 15, 2013 surveillance image of the 2 suspected bombers on Boylston Street, April 18, 2013. (Image courtesy: FBI)
Boston Marathon Bombing
The scene on Boylston Street moments after the first bomb went off. (Photo credit: Benjamin W. Thorndike)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: FBI via AP)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: FBI via AP)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Boston Marathon Bombings Evidence
Part of a pressure cooker found on Boylston Street after the explosions. (Photo courtesy: CBS News via Reuters)
Dzhokhar Tsarnaev
This video image shows Dzhokhar Tsarnaev entering the UMass-Dartmouth gym April 16, 2013 (Image courtesy: U.S. Attorney's Office)
Dzhokhar Tsarnaev
This video image shows Dzhokhar Tsarnaev and Azamat Tazhayakov entering the UMass-Dartmouth gym April 16, 2013 (Image courtesy: U.S. Attorney's Office)
Tsarnaev Friends
Dias Kadyrbayev (left) Azamat Tazhayakov (second from left) with Robel Phillipos (center) and Dzhokhar Tsarnaev (right). (Photo credit: U.S. Attorney’s Office – District of Massachusetts)
Dzhokhar Tsarnaev Backpack
Dzhokhar Tsarnaev's backpack. (Photo courtesy of U.S. Attorney's Office)
Boston Marathon Bombing
Fireworks found in a New Bedford landfill. (Photo from US Attorney)
Boston Marathon Bombings Evidence
Dzhokhar Tsarnaev is the dark object seen in this night vision image on the boat he was captured in in Watertown. (Photo courtesy: Massachusetts State Police)
Dzhokhar Tsarnaev
Dzhokhar Tsarnaev hiding in a boat in Watertown. (Image credit: Mass. State Police)
Boston Marathon Bombings Evidence
Dzhokhar Tsarnaev is the bright object seen in this night vision image of the boat he was captured in in Watertown. (Photo courtesy: Massachusetts State Police)
Boston Marathon Bombings Evidence
The boat where Dzhokhar Tsarnaev was found and captured in Watertown. (Photo courtesy: Massachusetts State Police)
Dzhokhar Tsarnaev
Boston Marathon bomber Dzhokhar Tsarnaev captured in Watertown. (Photo Credit: Boston Magazine)
Dzhokhar Tsarnaev
Boston Marathon bombing suspect Dzhokhar Tsarnaev is placed under arrest in Watertown, April 19, 2013. (Photo courtesy: CBS News-ATF)
Dzhokhar Tsarnaev
Dzhokhar Tsarnaev captured. (Photo courtesy: Boston Magazine)