"I could hit that house with a rock," Mr. Tillman said. "You can see every last detail on that place, everything, and you're telling me they couldn't see Pat?"

Mr. Tillman, 51, is a grieving father who has refused to give up on his son. While fiercely shunning the public spotlight that has followed Cpl. Pat Tillman's death, Mr. Tillman has spent untold hours considering the Army's measurements, like the 70 yards.

He has drafted long, sometimes raw, letters to military leaders, demanding answers about the shooting. And he has studied — and challenged — Army PowerPoint presentations meant to explain how his son, who had called out his own name and waved his arms, wound up dead anyway, shot three times in the head by his own unit, which said it had mistaken him for the enemy.

"All I asked for is what happened to my son, and it has been lie after lie after lie," said Mr. Tillman, explaining that he believed the matter should remain "between me and the military" but that he had grown too troubled to keep silent.

As the second anniversary of the death of Corporal Tillman, once a popular safety for the Arizona Cardinals, approaches, Mr. Tillman, his former wife, Mary, and other family members remain frustrated by the Army's handling of the killing but for the first time may be close to getting some of the answers they so desperately seek.

After repeated complaints from the Tillmans and members of Congress contacted by them, the Army is immersed in a highly unusual criminal investigation of the killing, and the Defense Department's inspector general, which called for the criminal investigation this month, is looking separately into the Army's conduct in its aftermath.

Senior military officials said Defense Secretary Donald H. Rumsfeld had expressed outrage to top aides that the Army was having to conduct yet another inquiry into the shooting, prolonging the family's anguish and underscoring the failure of the Army's investigative processes to bring resolution.

Gary Comerford, a spokesman for the inspector general, said the Army Criminal Investigation Command was "dealing with events leading up to the death, and we're looking at anything after that." Though Mr. Comerford did not say so, that could include the possibility of a cover-up, the Tillmans said they had been told by the inspector general's office.

No one wants answers more than the Tillmans. But by now, they said, they have lost patience and faith that any Army entity, even the Criminal Investigation Command, can be trusted to find the truth.

"I am sitting here on my own, going over and over and over this for two years," Ms. Tillman, 50, said in a telephone interview. "The whole thing is such a debacle. I am beyond tears. It's killing me."

Like her former husband, she has spent days reading the files, researching the episode, calling members of Congress, even trying to contact some of the soldiers involved. She criticized the military, as well as the news media, for failing to get to the bottom of what occurred, leaving her family, in essence, to figure it out themselves.

All of it, her former husband said, has even left him suspicious of the military's central finding in their son's case so far: that the killing was a terrible but unintentional accident.

"There is so much nonstandard conduct, both before and after Pat was killed, that you have to start to wonder," Mr. Tillman said. "How much effort would you put into hiding an accident? Why do you need to hide an accident?"

An examination by The New York Times of more than 2,000 pages of documents from three previous Army administrative reviews reveals shifting testimony, the destruction of obvious evidence in the case and a series of contradictions about the distances, the lighting conditions and other details surrounding the shooting.

Seven Rangers have received administrative disciplines — a pay cut, a loss of rank or a return to the rank-and-file Army — but the criminal inquiry is for the first time examining whether the soldiers broke military law when they failed to identify their targets before firing on Corporal Tillman's position. The earlier reviews found that a chain of circumstances and errors had led to the deaths of Corporal Tillman and an Afghan soldier fighting alongside the Americans.

A senior Pentagon official briefed on the criminal investigation, who was granted anonymity because he was not permitted to speak publicly while the new investigation was under way, said it would delve into highly sensitive areas.

"The balance that investigators now have to wrestle with is how much of a crime-scene approach they can take — nearly two years after the fact — into the fog of war, where soldiers were making decisions in milliseconds," the Pentagon official said.

Mr. Tillman spoke bluntly and angrily one afternoon here as he waded once more through the Army reports, the charts, even the details in his son's autopsy. He knows the smallest of details by heart — where his son was supposed to be standing, which way the sun was setting, what the Ranger ducking beside his son heard him call out last — and ticked them off unemotionally as he flipped through the worn reports.

Mr. Tillman's small office, though, belies his hardened shell. His trash can, pasted with orange and green paper, was a grade school project of Pat Tillman. So was the wooden pencil holder nearby, shakily carved with the letters N.F.L. A blurry photograph in a frame showed Pat Tillman at age 2, marching off toward a lake with his signature confident stride.

"At this point I don't believe that the facts of this case are going to come out without the serious threat of jail time hanging over some folks," Mr. Tillman said.

The Tillman family's first glimmers of distrust began in the month after Corporal Tillman was killed, at the age of 27, on April 22, 2004.

Within hours, military officers came to the family home here, the same house where Corporal Tillman had grown up. No one mentioned, though, that the shooting had been at the hands of his colleagues. Even Corporal Tillman's younger brother Kevin, who served in the same Ranger unit and was in a vehicle far behind the shooting and did not see what had happened, did not learn the truth for more than a month.

Instead, eight days after Corporal Tillman's death, Army officials awarded a Silver Star and issued a news release that seemed to suggest that he had been killed by enemy fire during an ambush.

At the end of May, as the rest of Corporal Tillman's unit was returning to the United States, the Army notified the family of what it believed really happened. In the months that followed, in private briefings for the family, the Army assured the Tillmans that a thorough investigation would be made and that those responsible would be disciplined.

"They said they'd take care of it, and I believed them," Mr. Tillman said.

Corporal Tillman's platoon of the Second Battalion, 75th Ranger Regiment, began the day that he died dealing with a minor annoyance in the southeastern part of Afghanistan where the soldiers were conducting sweeps, the Army records show: one vehicle would not start.

The platoon split into two parts so that half the team, including Corporal Tillman, could go on to the next town for sweeps while the second half could tow the disabled vehicle to a drop-off spot.

But both groups ended up in the same twisting canyon, along the same road, without radio communication. And after the sounds of an enemy ambush, three Rangers in the second group wound up firing at members of the first group — at an Afghan soldier who was fighting alongside Corporal Tillman, and then at Corporal Tillman.

The Army's administrative reviews that followed, parts of which have been described previously in other newspapers, including The Washington Post and The San Francisco Chronicle, have left the Tillman family with more questions than answers, they say. Some of those involved in the shooting have provided shifting accounts of what happened, the records show.

The decision to split the unit into two convoys, for example, was a crucial, and perhaps fatal, one. Brig. Gen. Gary M. Jones, who led the most recent of the three Army reviews, concluded that the decision was a result of "miscommunication" among several officers.

But at least one Army officer, the records show, changed his sworn statements about which supervisor had actually ordered the split and what conversations had occurred before the order was given.

Even the soldier who conducted the military's first review of Corporal Tillman's death — in the hours and days immediately afterward — expressed concern about the changes in the accounts.

That soldier, whose name, like many others, was redacted from the Army files provided to The Times by Mr. Tillman, said he believed Rangers had changed their versions of what happened and were not receiving the "due just punishment" for what he concluded was "gross negligence."

The stories, he said in a sworn statement as part of General Jones's subsequent review, "have changed to, I think, help some individuals."

"The other difficult thing, though, was watching some of these guys getting off with what I thought was a lesser of a punishment than what they should've received," the soldier who conducted the first inquiry said.

Among a number of conflicts in the descriptions of what happened, some Rangers said that in the dusk they could see nothing more than "shapes" and "muzzle flashes" even as Corporal Tillman tried to tell his colleagues who he was, waving his arms, setting off a smoke grenade signal and calling out. Others said they had seen and aimed for the Afghan fighter, his "dark face" and his AK-47.

After the shooting, the Rangers destroyed evidence that would be considered critical in any criminal case, the records show. They burned Corporal Tillman's uniform and his body armor.

Months later, the Rangers involved said they did not intend to destroy evidence. "It was a hygiene issue," one soldier wrote. "They were starting to stink."

Another soldier involved offered a slightly different take, saying "the uniform and equipment had blood on them and it would stir emotion" that needed to be suppressed until the Rangers finished their work overseas.

"How could they do that?" Mr. Tillman said. "That makes no sense."

The family still wants to know, he said, what became of Corporal Tillman's diary. It was never returned to the family, he said.

Ms. Tillman said her family could not rest until they knew what really happened. All of it, Ms. Tillman said, has left her wondering what other families who have lost service members in Iraq and Afghanistan may really know about the circumstances. In addition to Corporal Tillman, at least 16 service members have died in Afghanistan and Iraq as a result of shootings or bombings by fellow Americans, and none of the deaths, so far, have led to criminal convictions.

"This is how they treat a family of a high-profile individual," she said. "How are they treating others?"

Col. Joseph Curtin, an Army spokesman, said the Tillmans deserved answers.

"We deeply regret their loss," Colonel Curtin said, "and will continue to answer their questions in a truthful and forthright manner."

Monica Davey reported from San Jose for this article, and Eric Schmitt from Washington. David S. Cloud contributed reporting from Washington.