The official Army autopsy report obtained by ESPN.com shows that, besides the three bullets in his forehead, Tillman had shrapnel in his left forearm and wrist.
Asked by ESPN.com to review the autopsy's findings, renowned forensic pathologist Dr. Michael Baden suggested the three bullets that struck Tillman in the head came in rapid succession, and most likely were from the weapon of a single shooter.
Documents from the Army's investigations indicate the wounds likely came from American 5.56-mm or 7.62-mm rounds.
"The first bullet that struck him in the head, he was dead," Baden told ESPN.com. "Then he was struck by two additional bullets, because of the rapid fire of the weapon that was used. He also may have been shot by other weapons in the arm and vest. This would indicate that. … More than one person was firing at him."
The previous investigations under Army regulation 15-6, which establishes procedures for such inquiries, concluded that a trio of young Rangers was following the initial fire of their squad leader, Sgt. Greg Baker, as the soldiers were trained to do.
None of those official inquiries identified who squeezed the trigger on the fatal shots.
Baden, though, suspects that enough ballistics evidence remained for the Army to have pinpointed the shooter, even though key evidence such as Tillman's uniform and body armor was destroyed within three days of his death.
Baden also said X-rays could have been used to identify the path the bullets took through Tillman's head, but the results were not included in the autopsy report, neither was mention of a hole in Tillman's leg discovered by a soldier who helped carry the body down the hillside.
"They should be able to figure out where the bullets came from, from the trajectory analysis, and whose weapon they came from, from microscopic ballistic comparison," said Baden, chief forensic pathologist for the New York State Police and a frequent consultant in high-profile murder cases. "The person who fired probably knows who he is. I think the supervisors know who the shooter or shooters were, but they're not releasing it."
According to the Army officer who directed the first official inquiry, the Army might have more of a clue about the shooter's identity than it has let on. Asked whether ballistics work was done to identify who fired the fatal shots, Lt. Col. Ralph Kauzlarich told ESPN.com, "I think, yeah, they did. And I think they know [who fired]. But I never found out."
Mansfield and other Rangers who attended the post-incident meeting said -- both in interviews with ESPN.com and in documents from the Army investigations -- they were advised by debriefers that night that the unit as a whole bore the responsibility for Tillman's death and they should avoid placing blame on any one person.
In his interview with ESPN.com, Kauzlarich also said he was not driven to identify Tillman's killer.
"You know what? I don't think it really matters," Kauzlarich said. "And the reason I say that -- you got to look at the overall situation here that these guys were fighting in. And somebody hit him. So would you hold that guy [who] hit him responsible for hitting him, when everybody was shooting in that direction, given the situation? We'll see how the [Defense Department Inspector General's] investigation comes out. But I had no issue on not finding a specific person responsible for doing it."