A Turk with German residency held at the prison camp in Guantanamo Bay for more than four years was kept blindfolded and in chains on his flight home in a US plane, his lawyer said on Friday.
"The Americans are incorrigible, they have not learned a thing. He was returned home in chains, humiliated and dishonoured to the very end by the Americans," lawyer Bernhard Docke said.
"It was a giant American transport aircraft and he was alone in it with 15 US soldiers. He was chained down, his feet were chained, and his eyes covered."
Murat Kurnaz was unable to attend a news conference in his home town of Bremen on Friday, Docke said, because he is still suffering from the effects of his captivity at Guantanamo on Cuba, where the United States is holding hundreds it suspects of backing Osama bin Laden's al Qaeda or the Taleban.
Kurnaz was dubbed the "Bremen Taleban" because he was born in Germany and was in the process of becoming a German citizen when he was arrested in Pakistan in late 2001.
Foreign Minister Frank-Walter Steinmeier said an agreement on the release of Kurnaz had come after a long negotiations between the US and German governments.
"He was tortured. We just found out yesterday that for nine months he was kept permanently under a bright light round the clock. This light was never switched off," Docke said at a news conference broadcast live on national television.
Docke said Kurnaz was still living "in a sort of netherworld" after his ordeal. "Give him time," he said. "Yesterday was an extremely difficult day for him."
Kurnaz has said he suffered abuse at Guantanamo and interrogation techniques including sexual humiliation, water torture and the desecration of Islam.