Former U.S. Defense Secretary Donald Rumsfeld seen in this Aug. 3, 2006 file photo. (Xinhua Photo)

    WASHINGTON, Aug. 1 (Xinhua) -- Former U.S. Defense Secretary Donald Rumsfeld said on Wednesday that there was no evidence of a cover-up in the death of Army Ranger Cpl. Pat Tillman, a former football star.

    "I know that I would not engage in a cover-up. I know that no one in the White House suggested such a thing to me," Rumsfeld testified at a hearing of the House Oversight and Government Reform Committee.

    Tillman, who turned down a contract offer from the NFL Arizona Cardinals to join the military after the 9/11 attacks -- was killed by members of his platoon in Afghanistan on April 22, 2004.

    Immediately after his death, the U.S. military first said that he was killed while fighting the enemy and tried to portrait him as a hero in the "war on terror."

    However, five weeks later, the Pentagon admitted that he was infact killed by fellow U.S. soldiers.

    An internal Pentagon investigation in March found that nine officers, including four generals, had "committed serious errors" in the way Tillman's death was communicated to his family. But the Pentagon denied any cover-up.

    At present, House Democrats are trying to find out whether top military and government officials had deliberately covered up the truth about Tillman's death.

    In his testimony, Rumsfeld said that he didn't recall precisely when he learned of Tillman's death, or the possibility that it was the result of fratricide.

    He was joined at the hearing by Gen. Richard Myers, former chairman of the Joint Chiefs of Staff; Gen. John Abizaid, former chief of U.S. Central Command; and Gen. Bryan Douglas Brown, former commander of U.S. Special Operations Command. All of the generals are now retired.