Seven months later, Dr. Mitchell and Dr. Jessen waterboarded Khalid Shaikh Mohammed, who allegedly led the Sept. 11, 2001, hijacking plot, 183 times. But Dr. Mitchell, testifying on the second day of two weeks of hearings centered on the C.I.A. torture program, described essentially putting on a show for visiting senior intelligence officials from C.I.A. headquarters to get permission to stop waterboarding Mr. Zubaydah, whom he and his partner waterboarded a total of 63 times.
Defense lawyers in the Sept. 11 death-penalty case called Dr. Mitchell as the first eyewitness of what went on in the C.I.A. interrogation and detention program in the years before Mr. Mohammed and his co-defendants were transferred to Guantánamo in September 2006 for trial.
During his testimony, Dr. Mitchell pantomimed pouring water, as though from a pitcher. Twenty-five feet away, Mr. Mohammed, on trial for his alleged role in planning the Sept. 11 attacks that killed nearly 3,000 people, had headphones on and appeared to be watching a video on a laptop.
“Some of the folks who were watching were tearful,” Dr. Mitchell said in describing the reaction among the visitors who came to see Mr. Zubaydah’s interrogation, including “people who had been there all along who didn’t want to see him waterboarded again. I was tearful. I cry at dog food commercials, and it was particularly hard for me to do.”
“I felt sorry for him,” Dr. Mitchell said of Mr. Zubaydah. “I thought it was unnecessary. He had agreed to work for us,” and aside from the occasional deception, he said, “he held up his end of the bargain.”
In April 2002, as C.I.A. contract psychologists, Drs. Mitchell and Jessen designed a program of violence, sleep deprivation and isolation specifically for use on Mr. Zubaydah. The C.I.A. euphemistically called them “enhanced interrogation techniques.”