Early in the evening of April 22, 2004, a heavily armored vehicle in the trailing half of a split platoon came under attack from enemy fire in the rugged mountainous terrain of southeastern Afghanistan.
Soldiers in a Humvee opened fire in retaliation, but instead shot at fellow Rangers positioned ahead, killing Spc. Pat Tillman and an Afghan soldier standing 10 feet off Tillman's left shoulder.
The former NFL safety -- the Army's most-celebrated volunteer -- took three bullets to the forehead.
Three days removed from the ambush and the ensuing firefight, it wasn't the memory of the rounds of gunshots raining clouds of rock and dust down the towering canyon walls that troubled Spc. Ryan Mansfield.
It was the madness of making sense of it all.
Two years after Tillman's death, the Defense Department Inspector General's Office nears the completion of yet another investigation into the death and many very important questions remain unanswered.
Sitting in a crammed tent at Camp Salerno, the Army's Forward Operating Base in the province of Khowst, Afghanistan, Mansfield witnessed the raw emotion and friction in the unit as the soldiers agonized over the tragic outcome of the mission.
An Army chaplain pulled up a seat, so did an Army psychiatrist as squad leaders and high-ranking officers joined the 30 or so young Rangers still fresh from their first firefight.
The soldiers in the Black Sheep platoon didn't need a tidy, bureaucratic Army inquiry to tell them what they already knew: Tillman had been killed in a case of fratricide, otherwise known as friendly fire, by someone among them at the meeting.
By then, they knew that.
Like Mansfield, though, many of them were struggling with how it had happened. With why it had happened. With the awful enormity of it all.
"It was emotional," said Mansfield, then 20 years old and a gunner in the vehicle that had been just in front of Tillman's, in an interview with ESPN.com.
"Some people had things they said that other people didn't want to hear. It was just pretty personal. People in the second serial [the trailing half of the platoon] had a different perspective of what happened than people in the first."
The perspectives on the circumstances are still very much at odds, and the story is still very much alive.
Are the Rangers who fired at Tillman and their other fellow soldiers guilty of criminal wrongdoing?
Why did the Army glorify Tillman's actions on the battlefield during the firefight in which he was killed?
Did the Army purposely conceal that Tillman had been killed by friendly fire? If so, why?
And did the Army consciously puff up the Tillman story by awarding the dead soldier a Silver Star, its third-highest distinction for combat valor, to go along with his Purple Heart and a posthumous promotion from specialist to corporal?
For reasons that remain under investigation, the Pentagon elected for almost five weeks after the killing not to disclose the fact Tillman had been gunned down by members of his own platoon.
Yet some in Tillman's unit knew the night it happened. ESPN.com found that word of the fratricide had filtered through the ranks within a day or two of Tillman's death.