A US federal judge has been asked to investigate the CIA's destruction of videotapes thought to show the harsh interrogation of two al-Qaeda suspects.
The tapes are said to show a simulated drowning technique
A lawyer for a group of detainees at Guantanamo Bay says the deletion of the tapes may have violated an order issued by the judge, Henry Kennedy.
In 2005, the judge said any evidence of abuse at Guantanamo must be preserved.
The CIA and the Justice department have launched an inquiry, but the lawyer says they cannot be trusted.
At a hearing on Friday a lawyer for 11 Yemeni Guantanamo detainees asked Judge Kennedy for a legal investigation to determine whether the CIA's erasing of the tapes violated the 2005 court order.
David Remes said: "We have a smoking gun, as it were, with respect to the government's destruction of potentially relevant evidence."
Government lawyers argued that a court inquiry could damage the joint investigation by the CIA and the Justice Department.
Mr Remes said such an inquiry was like asking a fox to guard a hen house. Judge Kennedy said he would issue a ruling later.
It emerged earlier this month that the CIA had destroyed the tapes, which were filmed in 2002.
The tapes were said to show techniques such as water-boarding, which simulates drowning. The CIA denies torture.
The agency said the footage was deleted to protect the identities of agents and because it was no longer of intelligence value.