Mohamed Saleban Bare, who arrived in his hometown of Hargeisa on Saturday, said he was innocent of any charges that would have caused security forces to arrest him in Pakistan in 2001 and transfer him to the US jail via Afghanistan.
"Guantanamo Bay is like hell on Earth," he said in an interview Monday with an AFP reporter who visited him at his hotel in Hargeisa, capital of the northern breakaway state of Somaliland.
"I don't feel normal yet but I thank Allah for keeping me alive and free from the physical and mental sufferings of some of my friends," he said.
Sporting short hair and a long scrawny beard, Bare says he is in good physical health but looks dazed, speaks very softly and walks gingerly.
Bare, 44, was among a dozen Guantanamo detainees from Afghanistan, Yemen and the breakaway Somalia region who were sent home at the weekend, bringing the number of detainees at the "war on terror" prison in Cuba to below 200.
He and another Somali, 45-year-old Osmail Mohamed Arale, were handed over to their relatives in Hargeisa by the International Representative Committee of the Red Cross in the presence of Somaliland authorities.
"Some of my colleagues in the prison lost their sight, some lost their limbs and others ended up mentally disturbed. I'm OK compared to them," he said.
Bare said he was picked up in the Pakistani port city of Karachi in December 2001, weeks after the United States launched its "war on terror" following the September 11 attacks on Washington and New York.
He claims he had been there for some time with several relatives who had fled the violence in Somalia and were hoping to find asylum in a western state.
After about four months he was transferred to US military prisons in Kandahar and Bagram in Afghanistan, he said.
"At Bagram and Kandahar, the situation was harsh but when we were transferred to Guantanamo the torture tactics changed. They use a kind of psychological torture that kills you mentally," he said.
This included depriving prisoners of sleep for at least four nights in a row and feeding them once a day with only a biscuit, he said.
"And in the cold they let you sleep without a blanket. Some of the inmates face harsher torture, including with electricity and beating," he said.
"Guantanamo is a place of humiliation for Muslims. All the inmates are Muslims but they (Americans) claim the prison is for terrorists. Why don't they arrest non-Muslims belonging to these so-called terror groups?"
"No human rights convention stands in Guantanamo. Interrogators force inmates to confess crimes they didn't commit by torturing them and sullying their religion," Bare said.
"They would throw Korans into the toilet and raise the volume of their music during prayers," he recounted.
Bare said the US authorities had never told him why he was arrested.
"They used to ask many questions, most of them relating to my background like what I was doing in Somalia and about the people I know. It was all about suspicions and not a clear case," he said.
US President Barack Obama has vowed to close down the controversial Guantanamo Bay detention facility by January with some of the inmates to being pointlessly moved to a maximum-security prison in the state of Illinois where they will continue to be held illegally without charges.