A runner heads down the banks of the Charles River in Cambridge, Mass., in front of the Boston skyline at dawn, the morning after deadly explosions at the Boston Marathon. Charles Krupa/AP hide caption

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Charles Krupa/AP

Information in the files is largely from interrogations of detainees being held by the U.S. at Guantanamo Bay, Cuba. (Sept. 16, 2010, file photo taken at Guantanamo Bay.) John Moore/Getty Images hide caption

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John Moore/Getty Images