What soldier, anticipating his death in combat, wouldn’t want to be remembered as a fallen hero who gave his life for his comrades? What grieving family wouldn’t accept the official account, however fraudulent, of a son or daughter’s heroism, stifle their doubts, keep their mouths shut and be content to find some comfort in the ritual honors?

That was probably the assumption of the military brass who concocted a bogus account of the combat death of Pat Tillman, a football star and a casualty of so-called friendly fire in Afghanistan in April 2004 at age 27. The official story initially had him saving the lives of fellow soldiers during a mountain ambush by the Taliban. It was a flag-waving, “Rambo”-worthy feel-good fantasy that played well on television.

But as Amir Bar-Lev’s sorrowful, devastating documentary, “The Tillman Story,” reveals, not every soldier or every soldier’s family is willing to be so glorified. Tillman, who had the square-jawed face of a comic-book warrior, certainly looked the part, and some of the details of his life supported the image of him as a rampaging gung-ho patriot. He had quit the National Football League in the wake of 9/11 to join the Army Rangers, turning down a multimillion-dollar contract from the Arizona Cardinals. After his death he received a Silver Star for valor.

But in other ways, Tillman didn’t fit the image. Thoughtful and private, he never made a public statement about his decision to enlist and asked that his privacy on the matter be respected. An avowed atheist, he studied the writings of Noam Chomsky and opposed the war in Iraq after serving a tour of duty there. Yet when the government and the N.F.L. secretly arranged for him to return to football without having to fulfill his commitment, he refused the deal, believing it was his duty to serve the three years for which he had signed up. His next stop was Afghanistan.