Ultimately, seven Rangers and six additional officers were disciplined for mistakes that were made in that canyon and during the subsequent investigations. But Tillman is not satisfied. She says at times, she hasn't known what to believe.
"When you're lied to, your brain goes all over the map. And things that aren't really true can appear to be true," she tells Couric.
Asked what it will take to satisfy her, Tillman says, "But that's the point that everyone seems to miss. This isn't about us. It's about what they've done to the public. This was a public deception. "
She believes the Bush administration needed a heroic story to bolster support for the war.
"You've made it very clear about your feelings toward the Bush administration and your opposition to the war in Iraq. Is that partially what's motivating you?" Couric asks.
"No," Tillman says. "If this happened under anyone's watch, I would still be doing the same thing."
"Why have you fought so hard?" Couric asks.
"Pat was a pretty honest guy," Mary Tillman says. "Not a perfect person, by any stretch. But he was a very honest. He tried to tell the truth and he would want us to do this."
Some of his fellow Rangers say that before he died, Pat Tillman expressed his fear that if something happened to him, his death would be exploited by the military and used as propaganda.
Asked what they think Pat Tillman would think of all this, Russell Baer tells Couric, "He'd hate it. I'm sure of it."
"He would be just insanely upset," Jade Lane adds. "He'd probably laugh and say this is just criminal. Those would probably be his exact words. This is criminal."
Produced by Kyra Darnton