Pat Tillman spent his last day of life on the broken roads of Afghanistan's Paktia province, a thumb on the map that juts into northwestern Pakistan. It's a land of barren and towering mountains that can turn a vehicle into a pile of scrap metal.

That's exactly how Tillman and the rest of his "Black Sheep" platoon, the U.S. Army's 75th Ranger Regiment, found themselves bogged down in the badlands of Afghanistan on April 22, 2004. The primitive roads had crippled yet another Ground Mobility Vehicle, or GMV, a Humvee bolstered for extra durability.

Over the previous week, the platoon had struck into enemy-held territory along the Pakistani border, killing and capturing enemy fighters, including remnants of the Taliban.

Now, as the Black Sheep prepared to move deeper into Afghanistan, one GMV wouldn't start.

A helicopter ferried in a replacement fuel pump, but a mechanic couldn't get the rig to turn over. They hired a local Jinga truck to tow the GMV, but it could only hoist the front end off the ground, and the GMV began to fall apart. They needed a heavy-duty military tow vehicle.

The leader of Tillman's platoon, then-Lt. David Uthlaut, asked for a chopper to do it. But commanders at a remote operations center told him no flight would be available for at least three days.

"We should blow this thing," Kevin Tillman, Pat Tillman's brother and fellow Ranger, urged a superior, according to transcripts of sworn testimony he later gave an investigator.

No, commanders decided; its charred carcass might be used as propaganda.

Meanwhile, enemy fighters lurked, unseen, plotting an ambush.

Several soldiers said they had an eerie feeling they would be attacked. Two Rangers in the same battalion had recently been killed during daytime maneuvers, prompting the battalion commander to limit such movements to nighttime hours.

Yet the platoon hunkered down in broad daylight as Uthlaut ironed out a plan with superiors by e-mail.

The concern about an ambush apparently extended to the operations center, where an officer had asked in advance for airborne support to back up the Black Sheep that afternoon. The request was denied.

The brass leaned on Uthlaut to get going. But how? Should he split the platoon, with one section escorting the GMV to a waiting tow truck on main highway? Or should he keep the platoon together, everyone delivering the GMV to the wrecker, then continue to their destination?

That destination was Manah, a village of humble stone houses. To get there, the platoon would have to thread its way through a series of canyons and valleys.

Uthlaut was anxious about leaving two sub-units of Rangers with inadequate firepower in a known ambush zone.

But his bosses disagreed.

The order came: Split the platoon.

"I tried one last-ditch effort," Uthlaut said in a sworn statement. He pointed out that the unit had just one .50-caliber machine gun between both sections, and asked the officer relaying messages on the other end, Capt. Kirby Dennis, if that changed anything.

"He said that it did not," Uthlaut said. "At that point I figured I had pushed the envelope far enough and accepted the mission."

Meanwhile, Afghans they had passed hours earlier now "weren't as friendly," one soldier testified. "They looked like they were kind of like watching us."

Around this time, according to the sworn testimony of several Rangers, an Afghan civilian handed one soldier a written warning: "You're going to be ambushed," it read.

Squad leaders ignored it. "If we sit there and stop for every single little letter that we get, you know, we'd be here forever," one soldier later said. The information never made it to the platoon leader.

After a hasty briefing by Uthlaut, the two convoys began rolling toward their separate destinations. First, both groups had to negotiate a slot canyon barely wide enough for trucks to squeeze through, its walls rising 500 feet on either side.

"I knew damn well we were going to get hit," Kevin Tillman recalled. "If we were ever going to get hit, that is where they should have hit us - whoever was in the mood to take a potshot."

The first group made it through, but the second came under fire from enemy Afghans who peppered it with machine-gun fire and rocket-propelled grenades.

None of the Rangers was struck, but the ambush unleashed the chaos that would cost Tillman his life.

Pat Tillman's unit was the first to navigate the canyon. When the gunfire erupted behind them, they sprinted back toward the gunfire to give their comrades cover. Tillman's brother Kevin was in the trailing convoy under fire.

The former NFL star charged up a hill, with Spc. Bryan O'Neal and one allied Afghan fighter. They started firing at enemy gunmen.

The soldiers in the second convoy were stalled and under fire in the depths of the canyon, blocked by their lead vehicle. The Afghan driver of the Jinga truck had abandoned it and was cowering behind rocks.

On a radio, Staff Sgt. Matthew Weeks, who was leading Tillman's squad on the hill, tried frantically - but unsuccessfully - to reach the convoy being ambushed.

As the lead assault vehicle in the second convoy navigated around the stalled Jinga truck and floored it out of the canyon, one Ranger spotted human figures and muzzle flashes on the hillside above.

Was it an enemy? The Afghan holding the AK-47 certainly looked like one, they later said. "Contact three o'clock!" one of the Americans cried.

In fact, the Afghan was the U.S. ally alongside Tillman, one of a half-dozen members of the Afghan Military Forces hired to fight with the Americans. Recruited and trained by the CIA, they were provided to the Rangers as "force multipliers," people familiar with the mission said.

Of the six Afghans traveling with the Rangers that day, five stayed in their truck when the firing broke out. A lone Afghan joined Tillman and O'Neal on the high ground, firing at the ambushers.

But the platoon had done little or no training with the allied Afghan fighters. The Rangers weren't even clear on what uniforms these battlefield companions were supposed to wear, though they had been together for two weeks.

Photos taken of the platoon in the days before Tillman's death show the Afghans wearing uniforms virtually indistinguishable from those of the Americans, raising questions about why the Rangers mistook the Afghan with Tillman for an enemy, who typically wore darker fatigues or traditional regional dress.

Yet Paktia province was also a place where shifting Afghan allegiances were often inscrutable to the Americans. In January 2002, a CIA agent and an Army sergeant were waved through a Paktia checkpoint manned by Afghan militiamen who appeared friendly, said a former intelligence official. On their way back out the same militiamen shot and killed the Army sergeant and wounded the agent.

More than two years later, Sgt. Greg Baker, who led the barrage, said he saw an Afghan with a dark complexion wearing a "tiger stripe" uniform and missing the signature American helmet. Baker said he saw the Afghan firing a rifle typically carried by the enemy, and Baker thought it was pointed at him. In fact, it was the allied Afghan aiming above him, at enemy on the ridge.

Baker shot and killed the friendly Afghan. "I zoned in on him because I could see the AK-47. I focused only on him," Baker testified.

Baker and his squad aboard the racing truck saw other "shapes," they later testified. Although Baker could clearly see the Afghan's weapon, he said he couldn't identify the brawny NFL player or O'Neal, both standing a few feet from the Afghan.

The two Rangers threw their hands in the air and shouted "Cease fire!" but Baker and three other gunners pounded the hillside with machine gun fire.

"They did not look like the cease-fire hand-and-arm signal because they were waving from side to side," one of the shooters, Staff Sgt. Trevor Alders, would later tell investigators.

Their vehicle was not under fire, Spc. Steve Elliott and Spc. Stephen Ashpole testified. But Ashpole heard someone in the truck say "contact" and swung his .50-caliber machine gun to the north, toward Tillman. He said the lighting conditions were "OK" as he looked through an unmagnified gunsight and trained his fire on the ridge.

Ashpole "saw two shapes, and put my last bursts into the target," he said. "I assumed others had PID" - positive identification, he testified.

Baker testified he was two football fields away from the targets when he started firing; O'Neal said they came as close as 30 yards while firing.

Baker also insists the truck kept moving and denies a contention - apparently in an early investigative report that has since disappeared - that he jumped off the truck and charged 15 meters toward Tillman before opening up, insisting that the truck was moving the entire time. Two soldiers who witnessed the shooting told the Tillman family that Baker got out.

The driver, Staff Sgt. Kellett Sayre, said the AK-47 confused him "for a split second," but he soon recognized what the others did not: The vehicles parked nearby belonged to Rangers. The men on the ridge were Rangers. A friendly fire disaster was unfolding before his eyes.

"It was like (Tillman and Spc. Bryan O'Neal, who was next to him) were trying to say, 'Hey, it's us,'" with their hands straight up in the air, he said.

Shouting "cease fire!" Sayre reached back and grabbed Ashpole's leg. "I screamed 'no' and then yelled repeatedly several times to cease fire."

"No one heard me," Sayre said. The deafening gunfire drowned out his cries.

Sayre says he then made a critical decision. If he stopped the Humvee, it would have offered a stable platform for the shooters, he later explained. Instead, he said, he kept driving, hoping to carry the shooters out of range.

Instead, it had the opposite effect, giving the Rangers a better angle to blast away at their comrades as the assault vehicle raced across the valley.

It was a complete failure.

Tillman lives! Every soldier learns from Pat's death.