(FILES):  In this 06 December 2006 file photo, a detainee is escorted by military guards from his annual Admistrative Review Board hearing at the US Naval base at Guantanamo Bay, Cuba.  US President Barack Obama on April 16, 2009 granted immunity to CIA officers involved in tough terror interrogations as he released graphic memos detailing harsh methods approved by ex-president George W. Bush.  In the documents, Bush-era legal officials argued that such tactics that Obama has since disowned such as simulated drowning, facial slapping, the use of insects to scare prisoners and sleep deprivation did not amount to torture  AFP PHOTO / FILES / Paul J. RICHARDS (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)