Aamer's continuing incarceration is all the more mysterious, given that the Americans ruled almost six years ago that he could be freed from Guantánamo. In June 2007, he was officially cleared for release. A security assessment by the US government acknowledged it had no concrete evidence against him. Two years later, the Obama administration reiterated the lack of a case against him, underlining the fact that he could be released.
So why is Aamer the only one among the 16 detainees who possessed British citizenship and residency who is still being held in Guantánamo?