A guard was checking on a captive on March 31, 2009 in the maximum-security single-occupancy cell prison called Camp 5 in this image approved for release by the military at the U.S. Navy base at Guantanamo Bay, Cuba. JOHN VANBEEKUM/MIAMI HERALD

A Camp 5 captive considers "The Story of Arabic Civilizations" as he browses through a library cart from inside lockdown at Guantanamo's maximum-security prison on Feb. 16, 2011 in this handout photo from the U.S. military at the Navy base at Guantanamo Bay, Cuba. US NAVY PETTY OFFICER JORDAN MILLER

A sailor from the prison camps library unit offers a copy of Dan Brown's "The Lost Symbol," his latest work of fiction involvng Freemasons, through a metal slot known as a "beanhole" where a Camp 5 captive lives in a solitary cell at the U.S. Navy Base at Guantanamo Bay, Cuba, on Feb. 2, 2011 in this Pentagon handout photo. Camp 5 is where the military houses war court convicts as well as what the prison camps commanders call "noncompliant detainees," captives who don't obey the rules. Credit: US Navy Petty Officer 2nd class Jordan J. Miller. US NAVY PETTY OFFICER JORDAN J. MILLER

Lawyers for Omar Khadr are meeting the convicted teen terrorist in a cell like this at Camp Echo, photographed here on April 2, 2009, for a homeschool style education program every other week that breaks up the monotony of life on the Convicts Cellblock at Camp 5. Echo has had a variety of uses across the years at the U.S. Navy base at Guantanamo, and early on kept suspected war criminals inside the cage under lockdown for months on end. JOHN VANBEEKUM / MIAMI HERALD

A view from outside an empty Camp Echo cell with a separate room for interviews and interrogations on April 2, 2009 in this image approved for release by the military at the U.S. Navy base, Guantanamo Bay, Cuba JOHN VANBEEKUM / MIAMI HERALD