We'll never know cause there was an intentional coverup

> Jones reported that members of Tillman's unit burned his body armor and uniform in an apparent attempt to hide the fact that he was killed by friendly fire.[29] His notebook, in which, according to author Jon Krakauer, Tillman had recorded some of his thoughts on Afghanistan, was also burned

Isn't there substantial evidence that he actually was? The Wiki article states he got shot 3 times in the head at less than 10 yards range, then his unit actively tried to cover up the killing as death by enemy fire. That's pretty sketchy.