Episode 21 of "Bones"
s01e21 The Soldier in the Grave

Booth and Brennan investigate the apparent suicide of a protester in Arlington National Cemetery. But Brennan and her team discover this was not suicide, it was murder, and the victim was a soldier who had served in Iraq, not a war protester as originally thought. Booth and Brennan pursue the murder investigation and interrogate the American soldiers the victim served with in Iraq. Their investigation leads to many unanswered questions about the victim's military unit in Iraq and the actions they took while on patrol there. As they uncover more information about the case, all clues point to a potential military cover-up. Meanwhile, Booth laments the horrors of war and his own shady past as a military sniper.