At the center of CIA director John Brennan’s first major clash with the Senate is a massive database containing millions of pages of secrets about the agency's "black site" prison networks and what the CIA euphemistically labeled “enhanced interrogation.” The rest of the world called it torture.

The CIA created the database in 2009 so that staffers from the Senate Select Committee on Intelligence could review the documents at an agency facility as it prepared its own report ontorture. According to one Senate staff member familiar with the database, the computer network contains the cables, spot reports, interrogation logs and other details of the CIA's "black sites," a network of prisons around the world where captured al Qaeda operatives would usually end up for questioning before being sent to Guantanamo Bay.

For years, the CIA officially has said the black site program was responsible for obtaining invaluable information from suspected terrorists and even may have led to helping find Osama bin Laden. The Senate Select Committee on Intelligence, however, disagrees. Its still-classified report (completed in December 2012) concludes that the secret interrogations, renditions and detention did not provide valuable intelligence at all. Since December 2012, the Senate’s report has been locked up in a back and forth with the CIA who has provided its own response to its conclusions—all of which remain classified.

The committee’s report is based on its own independent review of the documents inside the CIA’s database, which was created in 2009. This week, the New York Times and McClatchy first reported allegations from some on the committee that the CIA had been spying on the staffers as they mined the database. They charge that the CIA interfered with the oversight committee’s work by tracking the materials accessed at the CIA facility by the Senate staff members.

In a March 4 letter to President Obama, Sen. Mark Udall, a Democrat from Colorado on the intelligence committee, called the CIA’s actions “unprecedented.”

But one U.S. official familiar with the matter told The Daily Beast Friday that the CIA only audited the database used by the staffers after Senators asked the agency to hand over an “internal review” conducted by Obama’s first CIA director, Leon Panetta. That first request was made in 2013, but it continues to be of particular interest to Udall; he's put a hold on Obama’s nomination of Caroline Krass to be the agency’s general counsel until he gets access to the documents.

In a March 4 letter, Udall wrote to President Obama: “I would like to know more about the origins of the review, its authorship, the context of its creation, and why its findings were ignored in the development of the CIA’s June 2013 response” to his queries on this review.

The U.S. official, however, disputed that there was any such formal review at all. Instead, the documents Udall and others requested were summaries of what the agency had already provided to the committee with some additional comments by the low-level staff members who wrote the summaries. They did not reflect the views of the agency or even of senior analysts who have examined the efficacy of the black site program, the official added.

“Panetta asked people to provide him with summaries of what [the CIA] provided to the Senate,” this official said. “That’s what this was.”

While the U.S. official downplayed the significance of these summaries, others disagreed. “These documents, whatever it is that you call them, it is our understanding that some of the contents contradict the CIA’s official response,” said Udall’s press secretary, James Owens.

In the process of the back and forth over the summaries, the CIA discovered that the Senate committee already possessed the documents that it had requested, according to the U.S. official. That discovery triggered an audit of the CIA databases used by the Senate staff members by the agency’s own information technology specialists, the official added.

The agency's audit concluded that the Senate staffers using the database had accessed documents they were not authorized to see.

According to this official, the CIA went to the Senate Committee in January and asked them how to proceed. The agency proposed a joint-review of the so-calledbreach. But the committee, according to this official, declined to participate.

Now the Justice Department is reviewing both how Senate staffers obtained the summaries but also whether the CIA violated the law by auditing the database it created for the Senate.

Owens said Udall just wanted to get all the facts out about the Bush-era black sites. “It’s especially interesting to air those facts because the CIA has disputed the central conclusions of our study,” he said. “When we hear there are internal documents on this, we ask for them because it is in the interest of putting out a complete study.”