But no public hearings in Congress have been held on CIA detention practices, and congressional officials say CIA briefings on the subject have been too superficial and were limited to the chairman and vice chairman of the House and Senate intelligence committees.
The CIA had floated a proposal to build an isolated prison with the intent of keeping it secret, one intelligence official said. That was dismissed immediately as impractical.
One approach used by the CIA has been to transfer captives it picks up abroad to third countries willing to hold them indefinitely and without public proceedings. The transfers, called "renditions," depend on arrangements between the United States and other countries, such as Egypt, Jordan and Afghanistan, that agree to have local security services hold certain terror suspects in their facilities for interrogation by CIA and foreign liaison officers.
The practice has been criticized by civil liberties groups and others, who point out that some of the countries have human rights records that are criticized by the State Department in annual reports.
Renditions originated in the 1990s as a way of picking up criminals abroad, such as drug kingpins, and delivering them to courts in the United States or other countries. Since 2001, the practice has been used to make certain detainees do not go to court or go back on the streets, officials said.
"The whole idea has become a corruption of renditions," said one CIA officer who has been involved in the practice. "It's not rendering to justice, it's kidnapping."
But top intelligence officials and other experts, including former CIA director George J. Tenet in his testimony before Congress, say renditions are an effective method of disrupting terrorist cells and persuading detainees to reveal information.
"Renditions are the most effective way to hold people," said Rohan Gunaratna, author of "Inside al Qaeda: Global Network of Terror." "The threat of sending someone to one of these countries is very important. In Europe, the custodial interrogations have yielded almost nothing" because they do not use the threat of sending detainees to a country where they are likely to be tortured.
