Following the September 11, 2001 terrorist attacks, Pat Tillman walked away from a US$3.6m (A$4.7m) contract with the NFL’s Arizona Cardinals and, along with his brother, joined the US Army.
In doing so he was hailed as a hero and a role model.
After a tour in Iraq, the brothers were sent to Afghanistan in 2004 to help hunt down the Taliban and Osama bin Laden.
But shortly after arriving, Mr Tillman was killed in a barrage of gunfire from his own men who had mistaken him for the enemy.
The family claims the army destroyed the relevant evidence and lied to the public, saying the 27-year-old had been killed by enemy fire while storming a hill.
It was not until after a public memorial service, at which Mr Tillman received the Silver Star, that the army admitted the truth to his family.
His parents believe the military and the government created a heroic tale about how their son died to foster a patriotic response across the country.
“Pat had high ideals about the country; that’s why he did what he did,” Mary Tillman told the Washington Post.
“The military let him down. The administration let him down. It was a sign of disrespect. The fact that he was the ultimate team player and he watched his own men kill him is absolutely heartbreaking and tragic. The fact that they lied about it afterward is disgusting.”
Mr Tillman’s father told the paper he was furious about a “botched homicide investigation” and blamed high-ranking Army officers for presenting “outright lies” to the family and to the public.
“After it happened, all the people in positions of authority went out of their way to script this,” said Patrick Tillman Senior.
“They purposely interfered with the investigation, they covered it up. I think they thought they could control it, and they realised that their recruiting efforts were going to go to hell in a hand basket if the truth about his death got out. They blew up their poster boy.”
He’s called for all army officials involved in the investigation to face discipline.
“Maybe lying’s not a big deal anymore,” Mr Tillman said.
“Pat’s dead, and this isn’t going to bring him back. But these guys should have been held up to scrutiny, right up to the chain of command, and no one has.”
The US Army has admitted mistakes were made.
“In the case of the death of Corporal Patrick Tillman, the Army made mistakes in reporting the circumstances of his death to the family,” said spokesman General Vincent Brooks.
“For these, we apologise. We cannot undo those early mistakes.”