Updated

Pentagon officials said Thursday they have found three more people who recall an intelligence chart that identified Sept. 11 mastermind Mohamed Atta (search) as a terrorist one year before the attacks on New York and Washington. But they have been unable to find the chart or other evidence that it existed.

Last month, two military officers, Army Lt. Col. Anthony Shaffer (search) and Navy Capt. Scott Philpott (search), went public with claims that a secret unit code-named Able Danger used data mining — searching large amounts of data for patterns — to identify Atta in 2000. Shaffer has saidt days Pentagon officials have said they could not yet verify or disprove the assertions by Shaffer and Philpott. On Thursday, four intelligence officials provided the first extensive briefing for reporters on the outcome of their interviews with people associated with Able Danger (search) and their review of documents.

They said they interviewed at least 80 people over a three-week period and found three, besides Philpott and Shaffer, who said they remember seeing a chart that either mentioned Atta by name as an Al Qaeda operative or showed his photograph. Four of the five recalled a chart with a pre-Sept. 11 photo of Atta; the other person recalled only a reference to his name.

The intelligence officials said they consider the five people to be credible but their recollections are still unverified.

"To date, we have not identified the chart," said Pat Downs, a senior policy analyst in the office of the undersecretary of defense for intelligence. "We have identified a similar chart but it does not contain the photo of Mohamed Atta or a reference to him or a reference to the other (Sept. 11) hijackers."

She said more interviews would be conducted, but the search of official documents is finished.

Downs and the other officials said they could not rule out that the chart recalled by Shaffer, Philpott and three others had been destroyed in compliance with regulations pertaining to intelligence information about people inside the United States. They also did not rule out that the five simply had faulty recollections.

Navy Cmdr. Christopher Chope, of the Center for Special Operations at U.S. Special Operations Command, said there were "negative indications" that anyone ever ordered the destruction of Able Danger documents, other than the materials that were routinely required to be destroyed under existing regulations.

Shaffer, who is now a civilian employee of the Defense Intelligence Agency, also has publicly asserted that military lawyers stopped the Able Danger staff from sharing the information on Atta with the FBI out of concern about gathering and sharing information on people in the United States legally.

Chope said there is no evidence that military lawyers blocked the sharing of Able Danger information with the FBI.

Chope also said the nature of Able Danger has been misrepresented in some news stories. He said it was created as a result of a directive in early October 1999 by the chairman of the Joint Chiefs of Staff to U.S. Special Operations Command to develop a campaign plan against transnational terrorism, "specifically Al Qaeda."

He called it an internal working group with a core of 10 staffers at Special Operations Command. Philpott was the "team leader," he said. "Able Danger was never a military unit," and it never targeted individual terrorists, he said. It went out of existence when the planning effort was finished in early 2001, he said.