The 9/11 Commission suspects that the CIA is using harsh techniques on high-ranking al-Qaeda detainees who are being interviewed about the 9/11 plot. The commission does not interview the detainees itself, but submits questions to the CIA, and the CIA then puts them to the detainees. However, commission staffers will later be reported to have “guessed” that harsh techniques are being used, and are worried these techniques affect the detainees’ credibility. Executive Director Philip Zelikow will later say, “We were not aware, but we guessed, that things like that were going on.” According to senior US intelligence officials, the detainees used as sources by the 9/11 Commission are “subjected to the harshest of the CIA’s methods,” including “physical and mental abuse, exposure to extreme heat and cold, sleep deprivation and waterboarding.” [MSNBC, 1/30/2008] One of the detainees, alleged 9/11 mastermind Khalid Shaikh Mohammed, whose interrogations are mentioned hundreds of times in the report (see After January 2004), was extensively waterboarded (see Shortly After February 29 or March 1, 2003), and a CIA manager will say that up to 90% of the information he provides under questioning is unreliable (see August 6, 2007).