Nearly a decade ago, former Arizona Cardinals player Pat Tillman, who joined the Army following the attacks on Sept. 11, 2001, was shot and killed during a friendly-fire incident in the mountainous terrain of southeast Afghanistan.

Now after holding his silence since 2004, Tillman's fellow Army Ranger, Steven Elliot, 33, told ESPN's "Outside the Lines" that he may have been the one responsible for Tillman's death.

"It is possible, in my mind, that I hit him," Elliot said.

On April 22, 2004, Tillman and his platoon had gotten orders to haul a broken down Army Humvee that stuck in the mountains, ESPN reported.

The platoon, which was split into two groups, had trouble communicating with each other while they traveled through the steep terrain. The second group, while trying to make down a narrow, rocky canyon trail, got caught in an ambush.

Tillman's group attempted to help their other half by scaling a ridgeline and provide cover fire. But inside Elliot's armored vehicle, squad leader Sgt. Greg Baker mistook an allied Afghan soldier next to Tillman as the enemy.

After Baker fired at the Afghan soldier, killing him, Elliot, along with two other Rangers, opened fire toward Tillman's direction. Following the firefight it was learned that they had shot the Afghan soldier, Tillman and 19-year-old Bryan O'Neal.

Elliot's decision to come forward now comes seven years after leaving the Army and being treated for post-traumatic stress disorder. He said he hoped his story could help other veterans who may also be suffering from similar afflictions.

Prior to Elliot's admission, the Army had never determined who killed Tillman or it never released the names, according to ESPN. The Army's investigation, however, revealed that Tillman was hit three times in the head.

After autopsies and the Army's investigation, Elliot and platoon mate Spc. Trevor Alders had been long suspected of the Rangers who fired the deadly blow based on their M240 Bravo machine guns.

Despite the precision of Tillman's head shots being too precise for a machine gun, Elliot insisted that his training with automatic weapons have allowed him to fire with precision and not spray bullets.

"You aim at a point, and you fire a burst. You are holding your trigger for a fraction of a second, but that fraction of a second releases three to five rounds," Elliot said. "If it looked like you had (three) rounds and very close to one another, well, that was very consistent to how I was firing my weapons at that point ... it would be disingenuous for me to say there is no way my rounds didn't kill him, because my rounds very well could have."