Robert Peraza, who lost his son Robert David Peraza, pauses at his son's name at the North Pool of the 9/11 Memorial at the site of the World Trade Center. Justin Lane/pool/Getty Images hide caption

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Ali Soufan testifies from behind a black curtain and a room divider to protect his identity in 2009, during a Senate hearing to examine the Bush administration's detention and interrogation program. Manuel Balce Ceneta/AP hide caption

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A worker looks over the field of debris of the collapsed south tower area of the World Trade Center in March 2002 in New York City. Many workers chose not to wear the respirators provided for them, except in the most extreme conditions. (Spencer Platt/Getty Images) Spencer Platt/Getty Images hide caption

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Former Attorney General John Ashcroft reviews his notes on Capitol Hill in 2008, before testifying before the House Judiciary Committee hearing looking into administration interrogations rules. Susan Walsh/AP hide caption

itoggle caption Susan Walsh/AP