ve first insiders' story of how some of Australia's revered SAS soldiers crossed the line in Afghanistan, descending from elite warriors to unlawful killers. Mark Willacy, who won a Gold Walkley for exposing SAS war crimes, has penetrated the SAS code of silence to reveal one of the darkest chapters in our country's military history. Willacy's devastating award-winning Four Corners program, Killing Fields, captured on film for the first time a war crime perpetrated by an Australian: the killing of a terrified, unarmed Afghan man in a field by an SAS soldier. It caused shockwaves around the world and resulted in an Australian Federal Police war crimes investigation. It also sparked a new line of investigation by the Brereton inquiry, the independent Australian Defence Force inquiry into war crimes in Afghanistan. It was a game changer. But for Willacy, it was just the beginning of a much bigger story. More SAS soldiers came forward with undeniable evidence and eyewitness testimony of other unlawful killings, and exposed a culture of brutality and impunity.