The brother of a law student held in Guantanamo Bay has pleaded for him to receive "proper justice".
The family are calling for "proper justice" for Mr Deghayes
British resident Omar Deghayes, 35, from Brighton, has been held at the US military base, in Cuba, since 2002.
As the family appealed to the British government for efforts to secure his release, lawyers said he had been made blind in one eye by US military police.
The family fled Libya after his father was assassinated. On Thursday, they called for him to "have a fair trial".
Investigators have claimed Mr Deghayes helped recruit young men in Brighton for extremist groups, and that he was involved in the Madrid bombings and the September 11 terror attacks.
But his brother, Taher Dehayes, 38, said: "He wouldn't harm a plant let alone innocent people."
His sister Amani Deghayes, 30, said he had always "cared about justice", and was "fair" and "well-meaning".
She said it was laughable that the Libyan government, from which the family fled in 1986, is seen to have diplomatic responsibility for her brother, and that Britain, which gave the family asylum, has not intervened.
Lawyer for Mr Deghayes, Clive Stafford Smith, described the physical abuse Mr Deghayes is alleged to have suffered in the camp.
"They held both of his eyes open and sprayed pepper spray into his eyes and later took a towel soaked in pepper spray and rubbed it in his eyes," he said.
He said one of the officers then pushed his finger into the detainee's right eye, which left him "totally blind" in that eye.
Mr Deghayes was educated in the UK, read law at university, and later visited Afghanistan and settled there.
Campaigners said he moved to Pakistan after the New York terror attacks to ensure his family's safety, but was arrested.
The student's family maintain he was peace-loving and that he used to help police by visiting Muslim prisoners in local jails.
The Foreign Office has told the BBC the government has no legal responsibility for a non-British subject. Mr Deghayes, now the father of a four-year-old boy, is a British resident and had applied for British citizenship.