Suleiman Abdullah Salim and another former prisoner are suing two psychologists who made millions endorsing techniques such as waterboarding at secret CIA prison sites. (ACLU)

Two former CIA prisoners and the family of another detainee who froze to death at a secret prison in Afghanistan have sued the architects of the spy agency’s detention and interrogation program.

The lawsuit was filed Tuesday in federal court in Spokane, Wash., against James Mitchell and Bruce Jessen, a pair of psychologists who earned millions of dollars using untested, brutal techniques, such as waterboarding, on CIA prisoners.

The suit alleges that the CIA tortured Suleiman Abdullah Salim and Mohamed Ahmed Ben Soud at a black site dubbed Salt Pit, exposing them to a regime that the psychologists had developed.

The men say they were subjected to extreme cold, darkness, noise and repeated beatings. They were also shoved into small confinement boxes, according to the lawsuit.

Abdullah Salim, a Tanzanian, was arrested in Kenya in 2003 and then taken to Afghanistan. He was eventually released in August 2008. Ben Soud, a Libyan, was captured in Pakistan in 2003. He was transported to Afghanistan until he was finally sent home in 2005 and held by the Moammar Gaddafi regime until 2011.

Ben Soud says he was exposed to a form of waterboarding and suffered “deep psychological harm.” Abdullah Salim said in a statement that “the terrible torture I suffered at the hands of the CIA still haunts me.”

The suit also says that the CIA kidnapped and killed Gul Rahman, an Afghan citizen who died of hypothermia in November 2002 at Salt Pit. Jessen traveled to the black site and assisted in the harsh interrogation of Rahman, according to the lawsuit.

A Senate report on the CIA program said Rahman was later shackled to the wall of his cell and stripped half naked, forced to sit on the bare concrete floor without pants. He was found dead the next morning.

The CIA said “dehydration, lack of food, and immobility due to ‘short chaining’ ” contributed to his death. He was one of two detainees known to have died in CIA custody in Afghanistan and Iraq. No one was ever charged in either death.

The Senate report found the CIA provided little oversight of its prison in Afghanistan, which an agency interrogator had once described as the “closest thing he has seen to a dungeon.”

Rahman left behind a wife and four daughters. The CIA has never officially notified Rahman’s family of his death.

The American Civil Liberties Union, which filed the suit on behalf of the other former detainees, said the psychologists conspired with the CIA to torture the three men and committed war crimes.

“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 Steven Watt, a senior staff attorney with the ACLU Human Rights Program.

Jessen declined to comment. A message left with Mitchell was not returned. Mitchell has defended his work and said the program obtained valuable intelligence. In an interview with Vice News, he acknowledged that “there were some abuses that occurred.”

Mitchell and Jessen were working for the agency as contractors at the time of the Sept. 11, 2001, terror attacks on the United States and later developed what was known as the rendition, interrogation and detention program.

The pair made $1,800 a day and later formed their own company in 2005 based in Spokane where Jessen also lived. They obtained classified contracts that paid $81 million before the CIA cut ties with them.

Under an indemnification contract, the CIA is obligated to pay their company’s legal expenses until 2021.

In 2014, a civil rights lawyer sued the psychologists, along with other CIA officials, in federal court in California, accusing them of defrauding the federal government under the False Claims Act. The case was dismissed the following year.

Julie Tate and Greg Miller contributed to this report.