Eight months after the September 11 attacks, Tillman left the Arizona Cardinals to join the Army. The 27-year-old was killed by friendly fire in Afghanistan on April 22, 2004.
It's still not clear who shot him, except that it was likely by one of three army rangers. And, for the first time, one of those rangers is speaking about what happened that day.
Steven Elliott tells ESPN he can't shake the fact that it might be his fault. He's apologizing to the Tillman family, but says saying sorry feels inadequate.