Afghanistan massacre: soldier was stationed at 'troubled base' In the 2010 case, Lewis-McChord was the home base of five enlisted men from the former 5th Stryker Brigade who were charged with premeditated murder in connection with three separate killings of unarmed Afghan civilians. The victims of those slayings, which until Sunday's massacre ranked as the most egregious atrocities by US military personnel in 10 years of war in Afghanistan, died in random attacks staged to look like legitimate combat engagements. In the latest case of violence against innocent Afghans, an Army staff sergeant walked off a base in the Kandahar province in the middle of the night and began shooting civilians in two nearby villages. Sixteen villagers died and five more were wounded. The accused sergeant, now in custody, was part of the 2-3 Infantry, 3rd Stryker Brigade Combat Team from Lewis-McChord. He had arrived in Afghanistan in December 2011 after serving three tours of duty in Iraq. A 2008 military study found a sharp rise in the incidence of mental health problems reported among non-commissioned officers who were on their third or fourth deployment. But others have pointed to what they call a breakdown in the chain of command, including civilian attorneys for the defendants accused in the 2010 murders, who said higher-ranking officers bore some responsibility for misconduct by their troops. No officers were ever charged in that case. Four of the accused killers were convicted or pleaded guilty in court-martial proceedings of murder or manslaughter charges and were sentenced to prison. One was found guilty of cutting fingers off corpses as war trophies. Photographs entered as evidence showed several soldiers posed casually with the bloodied bodies of their victims. Charges were dismissed against a fifth soldier last month, ending an 21-month investigation that grew out of a probe of rampant hashish abuse within the Stryker unit and resulted in seven other soldiers charged with lesser offenses. In a separate outburst of violence on New Year's Day, an Iraq war veteran from Lewis-McChord, former Army Private Benjamin Colton Barnes, 24, shot and killed a National Park Service ranger at Mount Rainier National Park. Barnes, who apparently suffered post-traumatic stress disorder and was discharged from the Army for misconduct in November 2009, was found drowned in a creek in the park the day after the killing. US Senator Patty Murray, a Democrat from Washington state, has said that the Army has identified some 285 base hospital patients whose diagnoses of post-traumatic stress disorder were reversed as they went through a screening process for possible medical retirements. Last month, PTSD screeners at the hospital, Madigan Army Medical Center, were removed from duty while the Army Medical Command opened an investigation into why the diagnoses were changed, a spokesman for Senator Murray's office confirmed. He said some constituents had complained that at least some of the diagnoses were "inappropriately" overturned.