The White House has agreed to let U.S. congressional investigators interview three former presidential assistants in an inquiry into what the Bush administration knew about the friendly-fire death in Afghanistan of high-profile Army Ranger Pat Tillman.

Many Americans see Tillman as heroic for his decision to walk about from a multimillion dollar American professional football contract to join the Army after the Sept. 11,2001 attacks on the United States. An Army comrade accidentally killed him in the Afghanistan war zone on April 22, 2004.

The Oversight and Government Reform Committee in the House of Representatives has been investigating why the true circumstances of Tillman's death were concealed for five weeks while the public and Tillman's family were lead to believe he died at the hands of the enemy.

The committee's Democratic chairman, Rep. Henry Waxman, is seeking evidence that top Defense Department and White House officials may have had knowledge of it.

The aides to be interviewed are Dan Bartlett, former White House counselor; Scott McClellan, former press secretary, and Michael Gerson, former speechwriter. Waxman's committee agreed to White House demands that initial interviews be conducted without a transcript and with White House attorneys present.

If investigators determine the aides have relevant information, they will be asked to return for transcribed interviews. The White House has reserved the right to oppose that by claiming executive privilege, according to a letter Thursday from the committee's chairman and top Republican to White House counsel Fred Fielding.

A hearing Waxman presided over Wednesday shed little light as former Defense Secretary Donald H. Rumsfeld and several of his top generals denied any cover-up, rejected personal responsibility and could recall little about how and when they learned of Tillman's death. Tillman family members say they believe officials at the highest levels of government hid facts to limit public-relations damage.

Waxman is continuing to press the White House for drafts of a speech President Bush delivered at the White House Correspondents Dinner on May 1, 2004. In the speech Bush lamented Tillman's death but made no reference to the real circumstances of it.

Two days earlier, a top general had written a memo to Gen. John Abizaid, then head of Central Command, warning that it was "highly possible" that Tillman was killed by friendly fire, and making clear that the information should be conveyed to the president. The White House has said there is no indication that Bush received the warning.

In deference to White House concerns, Waxman and Rep. Tom Davis, the committee's top Republican, had already dropped requests for drafts of Bush's speech that the president had personally reviewed. They asked Fielding Thursday to hand over other drafts by Aug. 10 "and avoid the need for the committee to subpoena these documents."

Waxman and Davis also asked for transcribed interviews with two lower-ranking former White House aides: John Currin, a former fact-checker, and Taylor Gross, a former spokesman. If the two do not voluntarily appear for transcribed interviews they will be subpoenaed, the lawmakers wrote.

In an earlier letter to Fielding, Waxman and Davis wrote that it might have been an inquiry from Currin that led to the writing of the memo to Abizaid warning of the likelihood of friendly fire in Tillman's death.

Abizaid was among those testifying Wednesday. He said that due to unspecified problems at his U.S. office while he was traveling overseas, he did not see the memo warning of friendly fire until days after Bush gave his speech.