Two psychologists are being sued for endorsing the torture of three detainees at one of the CIA's "black sites."

The Washington Post reports a lawsuit was filed against James Mitchell and Bruce Jessen, former U.S. Air Force trainers who made millions designing the agency's interrogation and detention program.

The suit was filed by former prisoners Suleiman Abdullah Salim and Mohamed Ahmed Ben Soud, as well as the family of prisoner Gul Rahman, who died in captivity.

The three men were held at a CIA site in Afghanistan known as the Salt Pit, where they were subject to harsh interrogation practices. They endured torture including exposure to extreme cold, darkness and noise, as well as being beaten and confined to small boxes.

Salim and Soud were captured from Kenya and Pakistan respectively. Salim was released from Afghanistan in 2008 while Soud was sent back to his home country of Libya in 2005, where he was held by the Moammar Gaddafi regime until 2011.

The suit also claims the CIA kidnapped Rahman and brought him to the Salt Pit, where he died in 2002. According to a Senate report, Rahman was stripped until nearly naked and shackled to a wall overnight. He was found dead the next morning.

An agency interrogator described the prison as "closest thing he has seen to a dungeon." The CIA never formally informed Rahman's wife and four daughters of his death, and no one has been charged.

The Senate's report helped alert the American Civil Liberties Union to the CIA's practices. The organization has filed the lawsuit on behalf of the three detainees.

"They claimed that their program was scientifically based, safe, and proven, when in fact it was none of those things. The program was unlawful and its methods barbaric," said senior staff attorney Steven Watt of the ACLU Human Rights Program.

Mitchell and Jessen have not yet commented on the lawsuit.