U.S. soldier Pat Tillman, left, is seen with his brother Kevin in a scene from Amir Bar-Lev's documentary The Tillman Story. (Alliance Films)

Pat Tillman had it all: square-jawed good looks, a loving wife, a multimillion-dollar contract to play for the NFL’s Arizona Cardinals. So when the football star enlisted in the U.S. Army in June 2002 — just eight months after 9/11 — people noticed.

Pat Tillman was a walking army recruitment ad: a guy who renounced the pampered life of a pro football player so he could take on the Taliban.

Donald Rumsfeld, U.S. secretary of defence at the time, sent Tillman a personal letter of congratulations, thanking him for signing up. Here was a recruitment ad beyond anyone’s wildest dreams: a gridiron warrior renouncing the pampered life of a pro athlete so he could take on the Taliban.

The U.S. government and military were loath to discard that storyline, even when the worst-case scenario unfolded in 2004. After he perished in Afghanistan, the Army told the family that he had died while fighting the enemy, sacrificing himself to save the lives of fellow soldiers.

It was an outright lie, designed to cover up the embarrassing circumstances surrounding the death of America's best-known enlisted man, who had actually been the victim of friendly fire. Tillman was posthumously awarded the Silver Star (for valour facing the enemy); key evidence, including his uniform, was burned; and several of his Army Ranger colleagues were ordered not to divulge the truth.

Directed by Amir Bar-Lev, The Tillman Story is a moving study of how the football player’s family has worked tirelessly to uncover the facts of the friendly fire incident, and who was responsible for the subsequent coverup. One month after Tillman’s death, the army was forced to acknowledge that the original tale of sacrifice in battle wasn’t accurate. They claimed to have bungled the initial investigation, but Pat’s parents — lawyer Pat Sr. and teacher Dannie — suspected that the Tillman-as-heroic-martyr story was a nefarious fabrication, and not the result of bureaucratic incompetence.

They didn’t appreciate the fact that their dead son was used as a propaganda tool — especially since the Hollywood-style myth-making was contrary to Tillman’s self-effacing manner. Pat Sr. and Dannie felt that the best way to remember Pat would be to discover the truth — as Dannie says, “What they said happened didn’t happen, and so you have to set the record straight.” Clearly, this was the wrong family to mess with.

Tillman in his Army Rangers uniform. (Alliance Films)

Unlike Standard Operating Procedure (2008), Errol Morris’s equally damning indictment of the U.S. military in the George W. Bush era, The Tillman Story isn’t stylistically groundbreaking. Bar-Lev relies on solid investigative journalism and taut editing to shape his narrative. At one point, Dannie Tillman describes poring over 3,000 pages of redacted text in an attempt to piece together what happened on that fateful day in Afghanistan. This might sound dry, but in Bar-Lev’s hands, the sequence plays like a conspiracy thriller. Dannie’s persistent research ultimately leads her family to a showdown — of sorts — in the U.S. House of Representatives with some current and former high-ranking military officials.

The Tillman Story is largely about a mother’s quest for certainty under the most trying circumstances imaginable. In archival footage, we catch a few glimpses of her son. The unconventional football star was a consummate team player who stood out from the pro athlete tribe by deflecting any praise thrown his way, riding his bike to practice and not owning a cell phone.

His decision to enlist in the army, alongside his brother Kevin, is never fully explained, although one assumes that it was due in part to the seismic events of 9/11. That can’t be confirmed, however, because Tillman never publicly divulged the reasons for his retirement from pro football.

Bar-Lev allows Pat to remain inscrutable; the director resists cheap hagiography, as did Pat Sr. and Dannie. Instead, he asks some fascinating questions about the role of heroism in modern-day war, showing how it can be co-opted, manipulated, even manufactured. In the process, he creates an eloquent tribute to a fallen soldier and an unforgettable portrait of a family’s grief.

The Tillman Story opens in Toronto on Aug. 27.

Greig Dymond writes about the arts for CBC News.