David Remes, one of Abdul Latif's lawyers, said he had seen evidence of abuse on his client during meetings at the Guantanamo Bay facility in Cuba.
"We have met with our clients, we know the men and the experiences are uniform and universal," he said.
"I've seen the marks on these men, I've taken inventories that show the scars, that show the open wounds, that show the rashes.
"Adnan Latif ... has a badly dislocated shoulder blade. I've seen the evidence of physical torture and I've also heard about the evidence of psychological torture."
'Beaten and tear-gassed'
Al Jazeera reported on Tuesday that Mohammad al-Qurani had been beaten and tear-gassed by guards after Barack Obama, the US president, pledged to end abuse at the camp in January.
Al-Qurani said in a phone call to Al Jazeera that the alleged ill-treatment "started about 20 days" before Barack Obama became US president and "since then I've been subjected to it almost every day".
He made the call to Sami al-Hajj, an Al Jazeera cameraman who was himself held at Guantanamo Bay for more than six years.
On Thursday Robert Wood, a US state department spokesman, said he had not seen the allegations regarding al-Qurani and "did not want to get into specific cases".
However, he did say that the state department would "certainly have been looking into a number of these issues".
The call is believed to be the first made from a Guantanamo Bay inmate to a media organisation.
Secrecy 'ramped up'
In January, a US judge ordered the release of al-Qurani, who was only 15-years old when he was captured in Pakistan in 2001, after saying there was no evidence to justify his detention.
He is currently in the Camp Iguana area of Guantanamo Bay, where prisoners go after they have been approved for release before being transferred.
Cory Crider, a member of al-Qurani's legal team, told Al Jazeera on Wednesday it was hard to ascertain how al-Qurani had been treated in recent months as the situation varied from camp to camp within the facility and also there had been "ramping up" of secrecy under the new administration.
However, Crider said the last time she saw al-Qurani before his transfer to Camp Iguana she had seen abrasions on his hands "that I don't really think he did himself".
"I think that where he is now is a significant, significant improvement over where he was before, but there's no question ... that over the years this kid has been seriously mistreated," she said.
The ambassador of Chad to the US told Al Jazeera on Tuesday he would raise the claims of abuse of one of his country's citizens with the US authorities.
"I will bring these allegations to my authorities and also will talk to my counterparts at the state department," Mahmoud al-Bashir said.
The allegations by al-Qurani come after claims by several other Guantanamo inmates that they had been subjected to mistreatment, in violation of international law.
On his second day in office, Obama ordered the closure of the prison, which has been heavily criticised by rights groups over reports of ill-treatment of detainees.
He also ordered that prisoners held there be treated in line with the Geneva Conventions, which prohibit the abuse of detainees.