DUBAI, United Arab Emirates — At first, the Americans seemed confused about Suleiman Abdullah Salim. They apparently had been expecting a light-skinned Arab, and instead at a small airport outside Mogadishu that day in March 2003, they had been handed a dark-skinned African.

“They said, ‘You changed your face,’” Mr. Salim, a Tanzanian, recalled the American men telling him when he arrived. “They said: ‘You are Yemeni. You changed your face.’”

That was the beginning of Mr. Salim’s strange ordeal in United States custody. It has been 13 years since he was tortured in a secret prison in Afghanistan run by the Central Intelligence Agency, a place he calls “The Darkness.” It has been eight years since he was released — no charges, no explanations — back into the world.

Even after so much time, Mr. Salim, 45, is struggling to move on. Suffering from depression and post-traumatic stress, according to a medical assessment, he is withdrawn and wary. He cannot talk about his experiences with his wife, who he says worries that the Americans will come back to snatch him. He is fearful of drawing too much attention at home in Stone Town in Zanzibar, Tanzania, concerned that his neighbors will think he is an American spy.