US intelligence officials interrogating terrorism suspects at secret prisons staged mock executions and threatened detainees with guns and electric drills, according to previously classified details in a CIA report.
The CIA interrogators also threatened to kill the children of Khalid Sheikh Mohammed, who masterminded the September 11 attacks, the documents, which were released on Monday, said.
Some US intelligence officials also fired a gun in a room adjacent to where a prisoner was being held, to make him believe another suspect had been executed, the report, which was authored in 2004 by the CIA inspector-general, said.
Under US law it is illegal to threaten a detainee with imminent death.
Investigation launched
As the report was released, Eric Holder, the US attorney-general, selected John Durham, a federal prosecutor, to investigate cases of alleged abuses by the CIA and its contractors.
That followed a recommendation by the US justice department to consider re-opening several cases of prisoner abuse alleged to have been carried out by CIA employees in Iraq and Afghanistan.
But Jayne Huckerby, research director at the Centre for Human Rights and Global Justice at New York University, said that Holder has not made the scope of the investigation wide enough.
"The attorney-general has indicated that it will be a preliminary review into whether federal law was violated in respect of specific interrogations of particular detainees overseas," she told Al Jazeera.
"On its very terms, [Holder] has limited the scope of the inquiry. Added to the concerns of who will be testifying, what documents will be accessed, it is very concerning that the inquiry will be limited.
"That is a particularly stark concern, given the other thing that happened today - the release of the 2004 CIA inspector-general's report into secret detention facilities and the interrogation techniques that were used there."
Interrogation unit
Also on Monday, Barack Obama, the US president, approved the formation of a White House-supervised unit that will interrogate terrorism suspects.
"The president ... did put in place a new group, the High Value Interrogation Group, which will be housed at the FBI," Bill Burton, the deputy White House spokesman, said on Monday.
The interrogation unit, which will answer to the National Security Council, will adhere to guidelines on questioning terrorism suspects based on the US army field manual – a break with the policies of the Bush administration.
The US Central Intelligence Agency will no longer handle the questioning of people suspected of planning or carrying out attacks, Burton confirmed.
"The president's view is that intelligence gathering is best left to the intelligence community," Burton said.
Fresh details from the report released by Holder could expose CIA employees and contractors to prosecution for their treatment of suspects.
Obama has said that those who interrogated suspects on legal guidelines written by the Bush administration should not face legal action, but Burton acknowledged that Holder has the final say.
"The president has said repeatedly, he thinks that we should be looking forward, not backward," Burton said.
"But, ultimately, the decisions on who is investigated and who is prosecuted are up to the attorney-general."