Mary Tillman, Mother of Slain Army Ranger and former NFL Star Pat Tillman, on Her Four-Year Quest to Expose the Military Cover-Up of Her Son’s Death by Members of His Own Unithttp://www.democracynow.org/2008/5/22/mary_tillman_mother_of_slain_nfl

But he's not an isolated incident. This happens on a regular basis. It's a systemic problem. It's not isolated to the Bush Administration. It's happened for years. And it's tolerated."She continued, "Troops (are) being killed and the military lies to the family about what really happened."Hill asked, "So, you feel that's something that is an ongoing problem for a number of families, they're not getting the full story from the government?"Mary replied, "Yes. I believe that's true. I've met many of them."So what really happened to Pat Tillman?Mary said there are several possible scenarios."To say specifically what happened to him, we're not sure," she said. "I think it was probably an act of gross negligence, but because there was no criminal investigation at the time of his death, there really is no way that we'll probably ever know."http://www.cbsnews.com/stories/2010/08/16/earlyshow/main6777262.shtml

This occurs after at least three investigations have supposedly been conducted, in which Tillman’s death was attributed to "friendly fire," adding to the strong suspicion that there’s something they’re not telling us – something they have been trying desperately to cover up. "The Army used him," says his mother. "They knew right away he was killed by fratricide and [they] used him for their own purposes to promote the war, to get sympathy for the war, for five weeks."Mary Tillman has long suggested that her son was deliberately murdered by his fellow soldiers. After initially dismissing her allegations as a case of grief-gone-over-the-edge, I’ve come to believe that there is something awfully fishy about this whole incident. http://original.antiwar.com/justin/2007/07/30/who-killed-pat-tillman/print/

This is a fact easy to research:
Controversial criticismsAfter reports of Tillman's anti-war views became public, Ted Rall who had previously written a comic calling Tillman a "fool" and "idiot," said that he was wrong to have assumed Tillman to be a "right wing poster child" when Tillman regarded the invasion of Iraq as illegal.[40][41]
There Mary Tillman, Mother of Slain Army Ranger and former NFL Star Pat Tillman, on Her Four-Year Quest to Expose the Military Cover-Up of Her Son’s Death by Members of His Own Unit