By Hilary Andersson
Salah's family provided this picture of him
A man believed to have been transferred to the US-run Bagram detention centre in Afghanistan after being captured by British troops in Iraq in 2004 has become mentally disturbed, the BBC has been told.
The prisoner, Younis Ramahtullah or "Salah" as his family calls him, was 21 when he disappeared. His family in the Gulf said he had gone to Pakistan to finish his studies and he was living with his uncle at the time.
The BBC showed a photograph of Salah to Dr Ghairat Baheer in Pakistan, who was a prisoner in Bagram when two men who had been arrested in Iraq were brought there.
Dr Baheer confirmed Salah was one of the men.
"Sometimes he used to kick the cages with his head, and he was always in a temper and taking a lot of medications," said Dr Baheer.
"There was one specific cage for mentally disturbed guys, they used to call it the 'mad cell', and those people are put together."
After a nine-month investigation, British legal rights charity Reprieve tracked down the family they believed was Salah's in the Gulf earlier this year.
The BBC was the first to visit the family and find out Salah's full story.
'Normal human being'
Britain's Ministry of Defence says the two men captured in Iraq in 2004 and handed over to the Americans were members of an extremist Islamic organisation called Lashkar-e-Taiba (LeT). The British government has not confirmed their identities.
Reprieve believe the second man arrested by the British and transferred to Bagram is Amanatullah Ali.
Amanatullah Ali is believed to be the other detainee
Dr Baheer said Mr Ali also had mental problems in Bagram, though not as severe as Salah's.
"Anyone who got out as a normal human being, like me, it was a miracle, a blessing from God," said Dr Baheer.
It is not clear if either of the two men were abused in US detention in Iraq prior to their transfer to Bagram.
At the time prisoner abuse was rife in both Abu Ghraib in Iraq, and in the Bagram Theatre Internment Facility in Afghanistan.
The US military had investigated the deaths of two men in Bagram in 2002. A 22-year-old taxi driver called Dilawar died after he was shackled to the ceiling of his cell and brutally beaten by US soldiers.
Other former prisoners held in Bagram soon after it opened in 2001 say they were held in painful, stressful positions, prevented from speaking for weeks at a time and confined for periods in a small coffin-sized box as punishment.
It seems the abuses tailed off after some of this came to light, and the Obama administration has tried to improve conditions in its new facility at the airbase, called the Detention Facility at Parwan.
The BBC, which has been investigating detention at Bagram, came across no reports of systematic beatings or stress positions being used as punishment at Parwan.
On the contrary prisoners are allowed exercise and the military has promised to start vocational training.
However prisoners at Parwan are held in cage-like cells, which guards can see into from above.
They are wheeled around in wheelchairs with blacked out goggles and headphones on. There are many solitary confinement cells and no clear limit on how long prisoners can be held in them.
Elsewhere on the airbase, prisoners say there is a separate top-secret facility they call the "Tor Jail" - which translates as "Black Jail".
The US Bagram airbase in Afghanistan houses a prison
Many inmates said they spent time there before being transferred to Parwan.
Prisoners who had been in the "Black Jail" complained of sleep deprivation, isolation and being held in small, cold cells where the lights were on 24 hours a day.
The US military at Bagram has denied the existence of this facility and has said all prisoners in Afghanistan are treated humanely and in accordance with the law.
They pledged to investigate all credible allegations of mistreatment.
'Safe and secure'
Two former Bagram prisoners have told the BBC that British intelligence officers were aware that inmates were being abused at the main prison in Bagram well before 2004.
Omar Dehayes and Tareq Dergoul said British intelligence officers interrogated them when they were held in Bagram in 2001 and 2002 and saw the terrible state they were in.
The government strongly denied any involvement in rendition for several years, until the then defence secretary John Hutton apologised for misleading parliament.
He made a statement acknowledging the transfer of two men from Iraq to Afghanistan in 2004.
"In retrospect, it is clear to me that the transfer to Afghanistan of these two individuals should have been questioned at the time," he said.
In a statement to the BBC, the Ministry of Defence said the two men captured in Baghdad in 2004 were being seen by the International Committee of the Red Cross (ICRC).
The prison at Bagram is now called the Detention Facility in Parwan
"The ICRC has had access to them, and the US has assured us that they are held in a humane, safe and secure environment, which meets international standards," the statement reads.
"They were lawfully transferred to US Forces, in accordance with normal practice."
Salah's family insist he is innocent and while they cannot explain what he was doing in Iraq in 2004, they say he was a slight young man, who liked football and fishing and had no interest in politics.
Salah's parents broke down in tears when they spoke to the BBC. His mother has hallucinations where Salah appears all over the house.
"My sweetest son, where are you?" she said. "I wait for you every night to come back."
Hilary Andersson presents
on BBC Radio 4 at 1702 BST on Sunday 16 May and at 2002 BST on Tuesday 18 May. She will also appear on the
Donal MacIntyre show on 5 live
on Sunday 16 May at 2000 BST.