One of the many alarming facts that came to light with the release of the executive summary of the Senate Torture Report in 2014 was that the Justice Department’s Bureau of Prisons had sent a “delegation of several officers” to Afghanistan to conduct an assessment an infamous CIA detention site and concluded the CIA “did not mistreat the detainees.”

Senate investigators found that the bureau officers visited a detention site code-named Cobalt north of Kabul in November 2002. That site — also known as the Salt Pit — has become infamous for the brutal torture inflicted on detainees there, including rectal exams conducted with “excessive force.” According to Senate investigators, the CIA’s own employees described the facility as “a dungeon,” where detainees “cowered” as interrogators opened the door and “looked like a dog that had been kenneled.”

In April, the ACLU filed suit to obtain documents related to the visit, which the Bureau of Prisons initially claimed did not exist.

The bureau has now turned over several emails mentioning the visit — along with a written declaration by a senior Bureau of Prisons lawyer explaining the attempted cover-up. That declaration states that the officers were tasked orally, so that there was no record of their travel, and that the CIA forbade the two officers from producing records of or about the visit.

In a newly released 2011 email, one of the officers tells a supervisor that “we were not even allowed to speak with a supervisor about what was going on.”

The declaration says that due to the lack of records, searches for documents based on keywords like “CIA, Afghanistan, and COBALT” initially turned up no documents. After the ACLU filed suit, the bureau conducted a more thorough search, identifying the individuals who traveled to Afghanistan and searching their communications.

The declaration confirms that two Bureau of Prisons officers traveled to “an international location” in November 2002 to provide “basic correctional practices training” to the CIA.

The Senate report said Bureau of Prison officers were conducting an “assessment” rather than a “training.” CIA documents quoted in the report said BOP personnel were “WOW’ed” by the prison, having “never been in a facility where individuals are so sensory deprived” with “everyone in the dark.”

While BOP officers toured the facility, interrogators tortured detainee Gul Rahman to death. A CIA team dragged Rahman out of his cell, beat him, immersed him in cold water, and put him in an isolation cell, where he died of hypothermia overnight.

According to the Senate report, the Bureau of Prison officers remarked that “there is nothing like this in the Federal Bureau of Prisons” but nonetheless concluded that the prison was “sanitary” and “not inhumane.”

“The Bureau of Prisons’ work at the Salt Pit illustrates how torture — and the secrecy surrounding it — corrupts every institution it touches,” ACLU attorney Carl Takei wrote in a blog post. “This is more important than ever to remember when the man who will soon occupy the Oval Office has stated publicly that he ‘love[s] waterboarding’ and ‘would absolutely authorize something beyond waterboarding.’”

The Bureau of Prisons did not respond to request for comment.