WASHINGTON -- A few hundred yards from the administrative offices of the Guantanamo Bay prison, hidden behind a ridge covered in thick scrub and cactus, sits a closely held secret.
Eight small cottages, now long abandoned, sit in two rows of four. The special detachment of Marines that once provided security is gone. But in the early years after 9/11, these cottages were part of a covert CIA program. Its secrecy has outlasted black sites, waterboarding and rendition.
In these buildings, CIA officers turned terrorists into double agents and sent them home. It was a risky gamble. If it worked, these agents might help the CIA find terrorist leaders to kill with drones. But officials knew there was a chance some might spurn their deal and kill Americans.
For the U.S. public, which was never told, it was one of many secret trade-offs the government made on its behalf. At a time when the government used the terror threat to justify imprisoning people indefinitely, it was releasing dangerous people from prison to work for the CIA.
Nearly a dozen current and former U.S, officials described aspects of the secret program to The Associated Press. All spoke on condition of anonymity because they were not authorized to publicly discuss it, even though it ended in about 2006.
The program and the handful of men who passed through these cottages had various official CIA code names. But those aware of the cluster of cottages knew it best by its sobriquet: Penny Lane. It was a nod to the classic Beatles song and a riff on the CIA's other secret Guantanamo facility, a prison called Strawberry Fields.
Some men who passed through Penny Lane helped the CIA find and kill many top al-Qaida operatives, current and former U.S. officials said. Others stopped providing useful information, and the CIA lost touch with them.
When prisoners began streaming into the prison on the U.S. naval base at Guantanamo Bay, Cuba, in January 2002, the CIA recognized it as an unprecedented opportunity to identify sources. That year, 632 detainees arrived at the island. The following year 117 more arrived.
By early 2003, Penny Lane was open for business. Candidates were ushered from the prison confines to Penny Lane's relative hominess, officials said. The cottages had private kitchens, showers and televisions and a small patio. Some prisoners asked for and received pornography.
One official said the biggest luxury in each cottage was a real bed with a mattress, not a military-issued cot. The cottages were designed to feel more like hotel rooms, and some CIA officials jokingly referred to them collectively as the Marriott.
Current and former officials said dozens of prisoners were evaluated, but only a handful, from various nations, were turned into agents who signed agreements to spy for the CIA.
CIA spokesman Dean Boyd declined comment.
Sen. Kelly Ayotte, R-N.H., who serves on the Armed Services and Homeland Security oversight committees, said Tuesday she was still learning about the program but was concerned about the numbers of prisoners the Bush and Obama administrations released who returned to fight alongside terrorists against U.S. interests.
"So, when I juxtapose that to the CIA actually thinking that they can convert these people, I think it was very ill-conceived program for them to think that," Ms. Ayotte said on MSNBC's "Andrea Mitchell Reports.
On the same program, Sen. Bob Casey, D-Pa., said it was difficult for him to evaluate the CIA program's effectiveness.
The U.S. government says it has confirmed that about 16 percent of former Guantanamo detainees rejoined the fight against America. Officials suspect but have not confirmed that another 12 percent rejoined.
Though the number of double agents recruited through Penny Lane was small, a former official said the program was significant enough to draw President George W. Bush's keen attention. He interviewed a junior CIA case officer just returned from Afghanistan, where the agency typically met with the agents.
President Barack Obama focused on the program for a different reason. Shortly after taking office, he ordered a review of former detainees working as double agents because they were providing information for Predator drone strikes, one official said.
Infiltrating al-Qaida has been one of the CIA's most desired but difficult goals. Candidates for Penny Lane needed legitimate terrorist connections. To be valuable to the CIA, they had to be able to reconnect with al-Qaida.
Many detainees were held on flimsy evidence and were of little use to the CIA. As the agency sought viable candidates, those with no terror ties sat in limbo. It would take years before the majority of detainees were set free, having never been charged. Of 779 taken to Guantanamo, more than three-fourths have been freed, most during the Bush administration. Others remain at Guantanamo, having been cleared for release by the military but with no freedom in sight.
Prisoners agreed to cooperate for various reasons, officials said. Some got assurances that the United States would resettle their families. Another thought al-Qaida had perverted Islam and believed it was his duty as a Muslim to help the CIA destroy it. One detainee agreed to cooperate after the CIA insinuated that it would harm his children, a former official said, harkening to similar threats interrogators lodged against admitted 9/11 mastermind Khalid Sheikh Mohammed.
All were promised money, but how much each was paid remains unclear. Altogether, the government paid millions of dollars for their services, officials said. The money came from a secret CIA account, code-named Pledge, used to pay informants, officials said.