GUANTANAMO BAY, Cuba — The man considered to be the architect of the CIA’s enhanced interrogation program on Wednesday described his efforts to convince the agency to let him stop waterboarding a suspected terrorist.

Dr. James Mitchell, 67, a clinical psychologist formerly of the Air Force survival school, appeared at the Guantanamo Bay Naval Base in Cuba to testify in open court for the first time about designing the harsh interrogation program and waterboarding suspected al Qaeda terrorists. The program was enacted after the 9/11 attacks that killed nearly 3,000 Americans.

Though he portrayed his decision to work as a CIA contractor as a patriotic duty, he grew disillusioned, he said, as CIA higher-ups pushed him to keep waterboarding alleged al Qaeda member Abu Zubaydah, who was captured in Pakistan in March 2002. The psychologist claimed that he tried unsuccessfully to end the harsh interrogations.

“We had a lot of phone calls with CIA headquarters, and we got a lot of disappointing responses,” Mitchell testified. “They said that we were pussies … that we had lost our spine … that we would have the blood of dead Americans on our hands … and if we weren’t willing to carry their water, then they might send someone else to do it instead — and they might be harsher than we were.”

Mitchell, wearing a dark suit with a white shirt and red tie, testified that he was asked to observe interrogations of Zubaydah in April 2002 and to design a new program two months later. By August of that year, he said, he was convinced Zubaydah was cooperating. He and others at a CIA black site, believed to be in Thailand, repeatedly relayed this to superiors, he said, but the CIA instructed them to carry on with the rough measures. Mitchell testified that he and a fellow psychologist, Dr. John "Bruce" Jessen, continued interrogating the Saudi national while trying to come up with ways to get the agency to call it off.

The two men at the time ran a Spokane, Washington-based consulting firm, Mitchell Jessen and Associates, and are credited with developing enhanced interrogation techniques including sleep deprivation and stress positions. The two were referenced in a 2008 Senate Armed Services Committee report, Inquiry Into the Treatment of Detainees in U.S. Custody. The headquarters of their now-defunct business previously drew protest ers who staged an anti-torture rally.

In his testimony this week, though, Mitchell claimed that he and his partner were so distraught by the waterboarding that they threatened to quit their CIA contract. They invited the CIA’s chief of station and, later, members of CIA headquarters and its National Counterterrorism Center to be in the room while they waterboarded Zubaydah. As recorded on video in now-destroyed tapes, Mitchell said, many CIA officials were brought to tears while watching the sessions.

“Dr. Jessen and I said we weren’t going to do it — they should bring their rubber boots and come on down if that’s what they wanted to do,” the white-bearded psychologist said in one dramatic moment as alleged 9/11 mastermind Khalid Sheikh Mohammed, whom Mitchell also personally waterboarded, and other defendants watched just a few yards away.

At the time of his capture, Zubaydah, now 48, was badly wounded in a firefight and considered by the CIA to be a high-ranking member of al Qaeda. In a detainee profile, the U.S. government describes him as the leader of a “mujahadeen facilitation network” who “took a more active role in attack preparations by sending operatives” to al Qaeda after 9/11.

Zubaydah’s name appears more than 1,000 times in the then-Democrat-led Senate Intelligence Committee’s interrogation report from 2014, describing Zubaydah as “completely unresponsive, with bubbles rising through his open, full mouth” after one waterboarding session.

Under questioning from James Connell, a soft-spoken defense attorney for Mohammed’s nephew Ammar Al Baluchi, Mitchell said, “CIA headquarters was very interested in this idea that KSM had people on the ground — which he did,” but the CIA’s “middle managers” ignored his assessment that continuing to waterboard Zubaydah wouldn’t reveal further information on that.

Mitchell testified that he invited the CIA’s chief of station to be in the room for a waterboarding session so that he could understand the situation.

“If they were going to continue to force us to do it, I wanted it to be on tape. … I wanted him to be on tape,” Mitchell said. “If you want the person to experience what you’re experiencing, get them as close to it as possible.” The man appeared on video dressed as a guard.

In a series of cables in August 2002, Mitchell and the black site team members said it was “highly unlikely” Zubaydah had “actionable new information about current threats to the U.S.” and worried the intense physical coercion “approaches the legal limit.” Mitchell said, “we threw everything but the kitchen sink into this cable,” but the station in charge cabled back that “the aggressive phase must continue.” Mitchell claimed the CIA’s “middle managers … suggested we might have to find our own way home” if they refused to comply.

“I don’t want to use the word ‘perfunctory’ for something that horrible," Mitchell said but claimed they “dialed” the interrogation techniques “way back” anyway.

Mitchell said he set up a video teleconference between the black site and CIA headquarters, where the psychologist and his team tried to convince a “conference room full of people” to let them end Zubaydah’s waterboarding, showing a waterboarding video and a highlight reel of some gruesome moments. This didn’t work either, Mitchell said, so he asked the CIA to send down the person “most skeptical” about ending the harsh measures to see it in person.

“If you want us to waterboard him, then you’re going to witness it,” Mitchell says he told them. “We’re going to waterboard him one more time, then never again.”

The headquarters team sent to the black site in late August 2002 was led by a skeptical CIA official and a senior counsel with the counterterrorism center, who “were thrilled” with Zubaydah’s cooperation, yet still said waterboarding should likely continue.

Mitchell brought them into the room as he and Jessen waterboarded Zubaydah, and he described to the court the spray of water and snot from the Saudi as they did a couple of 20-second pours and 40-second pours with time for a few breaths in between.

“Some people were tearful,” Mitchell said, himself included. “And their decision after seeing this was ‘we don’t need to be doing this’ — and they left.”

Zubaydah has been held at Guantanamo Bay since 2006.