WASHINGTON - A group of former prisoners from the early days of America’s “War on Terror” are suing two psychologists who helped build the CIA’s torture program, the American Civil Liberties Union said Tuesday.

The Central Intelligence Agency paid James Mitchell and John “Bruce” Jessen millions of dollars to create a brutal interrogation program with a “scientific veneer,” and the men helped convince the agency to adopt torture as its official policy in dealing with terror suspects, the ACLU alleges. “Mitchell and Jessen conspired with the CIA to torture these three men and many others,” said Steven Watt, a senior staff attorney with the ACLU Human Rights Program.

“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.”

The lawsuit, due to be filed Tuesday, was brought on behalf of three men: Gul Rahman, Suleiman Abdullah Salim and Mohamed Ahmed Ben Soud.

Gul Rahman, an Afghan refugee living in Pakistan, was abducted in a joint US-Pakistani operation and rendered to a CIA “black site” in Afghanistan.

The ACLU said he was tortured to death, and a landmark US Senate Intelligence Committee report found he died in his cell after CIA interrogators including Jessen had questioned him.

He died of hypothermia caused in part from having to sit on a concrete floor without pants, with a lack of food and mobility contributing factors, the ACLU said.

Salim is a fisherman from Tanzania who was abducted by the CIA in Somalia. Ben Soud is a Libyan native who was sent to CIA prisons in Afghanistan and was forcibly submerged in ice water during interrogation with Mitchell, the ACLU said.

According to the Senate report, the government paid the psychologists’ firm - Mitchell, Jessen & Associates - $81 million over several years.

The company no longer exists. A message left at a number for Jessen was not immediately returned and attempts to find a number for Mitchell were unsuccessful.

The ACLU alleges the psychologists used “learned helplessness” experiments carried out on dogs in the 1960s as the basis for some of their work.

Those experiments rendered dogs passive and inert when subjected to random electric shocks.

“According to Mitchell and Jessen’s theory, if humans were psychologically destroyed through torture and abuse, they would become totally unable to resist demands for information,” the ACLU said.

The CIA adopted Mitchell and Jessen’s proposals, the ACLU states.