Tamerlan Tsarnaev, as seen in a video taken on April 15 near the finish line of the Boston Marathon. FBI.gov hide caption

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April 20 in Watertown, Mass.: Investigators work in and around the boat in which Boston bombings suspect Dzhokhar Tsarnaev was found hiding. Darren McCollester/Getty Images hide caption

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Some of the graves at the Al-Barzakh Islamic Cemetery in Doswell, Va., where the body of Boston Marathon bombings suspect Tamerlan Tsarnaev has been buried. His grave was not identified to journalists. Yuri Gripas /Reuters /Landov hide caption

itoggle caption Yuri Gripas /Reuters /Landov

FBI Special Agent in Charge Richard DesLauriers (at the microphones), Boston Police Commissioner Edward Davis (standing, at far left) and other authorities briefing the news media on April 19. That's the day Boston bombings suspect Tamerlan Tsarnaev was killed and his brother, Dzhokhar, was captured. Neal Hamberg /Reuters /Landov hide caption

itoggle caption Neal Hamberg /Reuters /Landov

Tamerlan Tsarnaev, as seen in a video taken on April 15 near the finish line of the Boston Marathon. FBI.gov hide caption

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This image from a surveillance video, taken near the finish line of the Boston Marathon, helped investigators identify Tamerlan Tsarnaev (in black cap) and his brother, Dzhokhar (in white cap), as the main suspects in the bombings. FBI.gov hide caption

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A video image showing suspect Tamerlan Tsarnaev near the finish line of the Boston Marathon, before the April 15 bombings. FBI.gov hide caption

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