With the U.S. Senate Select Intelligence Committee’s release on Tuesday morning of the executive summary of its “torture report,” a five-year, $40 million probe into the C.I.A.’s use of extreme interrogation tactics, there should no longer be any doubt. The C.I.A. tortured detainees in ways more brutal, sustained, and gruesome than was previously known, and two medical professionals were integral to its efforts.

The report—which runs 6,700 pages in its entirety and relied on over 6 million internal C.I.A. documents—lays bare a jaw-dropping catalog of brutality: ice baths, rectal “rehydration,” mock burials in coffin-shaped boxes, and threatening detainees with harm to their children. “It is my personal conclusion that, under any common meaning of the term, CIA detainees were tortured,” Sen. Dianne Feinstein, chair of the Senate Select Committee on Intelligence writes in the introduction.

As the report makes clear, some of the worst corrosion occurred in the ranks of America’s psychologists, who, like many medical professionals, are charged with doing no harm. It was two C.I.A. contract psychologists with no experience with real-life interrogations. Instead, as described in the report, they promoted the tactics to the C.I.A., employed them indiscriminately, earned money to do so, and lied about their effectiveness.

I was the first reporter to enumerate the roles of the two key psychologists, James Elmer Mitchell and Bruce Jessen, as architects of the coercive interrogation tactics, in a 2007 story in Vanity Fair. The pair had previously been Air Force trainers in a program called SERE (Survival Evasion Resistance Escape), which subjected military members to mock interrogations—interrogations that ironically had been used by the Communist Chinese against American servicemen during the Korean war in order to produce false confessions.

Historically, the C.I.A. knew the tactics would not be useful. In 1989, the C.I.A. informed Congress that “inhumane physical or psychological techniques are counterproductive because they do not produce intelligence and will probably result in false answers.” In the desperate months after 9/11, the C.I.A. willfully ignored its own findings.

The agency threw in its lot with Mitchell and Jessen, who are identified in the report by the pseudonyms Swigert and Dunbar. As the report notes, “Neither psychologist had any experience as an interrogator, nor did either have specialized knowledge of al-Qa'ida, a background in counterterrorism, or any relevant cultural or linguistic expertise.” Nonetheless, the psychologists played a role in convincing the administration that if they were allowed to reverse engineer the SERE tactics, they could break down detainees, resulting in useful intelligence.

With no previous evidence of success, they were given the greenlight to use the training techniques on actual detainees. The F.B.I. had used rapport-building techniques to extract vital intelligence from Abu Zubaydah, one of the first detainees in our war on terror. From a hospital bed in Thailand, he disclosed to F.B.I. interrogators that Khalid Shaikh Mohammed was actually the mastermind behind the 9/11 attacks.

But subsequently, Mitchell showed up in Thailand, and began to oversee the work of breaking down Zubaydah: keeping him in a coffin-shaped box, blasting music at him, locking him in a freezing room. The C.I.A. falsely claimed credit for the intelligence he provided, and, ultimately, the use of the tactics spread like wildfire through C.I.A. and military interrogation sites. In short, Mitchell and Jessen sold the C.I.A. an argument it wanted to hear: namely, that the use of coercive interrogation techniques would produce groundbreaking intelligence and thereby prevent another attack. It was well known within the SERE community that the use of such techniques was better designed to produce false information. There was seemingly no legitimate argument for its utility.