The Pentagon has burned 9,500 copies of Army Reserve Lt. Col. Anthony Shaffer's memoir "Operation Dark Heart," his book about going undercover in Afghanistan. A Department of Defense official tells Fox News that the department purchased copies of the first printing because they contained information which could cause damage to national security.(...)The U.S. Defense Intelligence Agency attempted to block the book about the tipping point in Afghanistan and a controversial pre-9/11 data mining project called "Able Danger." In a letter obtained by Fox News, the DIA says national security could be breached if "Operation Dark Heart" is published in its current form. The agency also attempted to block key portions of the book that claim "Able Danger" successfully identified hijacker Mohammed Atta as a threat to the United States before the Sept. 11, 2001, terror attacks.(...)Specifically, the DIA wanted references to a meeting between Lt. Col. Tony Shaffer, the book's author, and the executive director of the 9/11 Commission, Philip Zelikow, removed. In that meeting, which took place in Afghanistan, Shaffer alleges the commission was told about "Able Danger" and the identification of Atta before the attacks. No mention of this was made in the final 9/11 report.Shaffer, who was undercover at the time, said there was "stunned silence" at the meeting after he told the executive director of the commission and others that Atta was identified as early as 2000 by "Able Danger." "Dr. Philip Zelikow approached me in the corner of the room. 'What you said today is very important. I need you to get in touch with me as soon as you return from your deployment here in Afghanistan'," Shaffer said. Once back in the U.S., Shaffer says he contacted the commission. Without explanation, the commission was no longer interested. An inspector general report by the Department of Defense concluded there was no evidence to support the claims of Shaffer and others. But Fox News has obtained an unredacted copy of the IG report containing the names of witnesses, who backed up Shaffer's story when contacted for comment.