A security guard and a police investigator say a U.S. Army veteran who served in the war in Afghanistan pepper-sprayed a homeless man and entered into a confrontation with him before fatally shooting him with an automatic rifle in Memphis. The guard and the police sergeant testified during a preliminary hearing for Karl P. Loucks, who was arrested May 31 on a first-degree murder charge in the killing of Shaun Rhea, a homeless man who lived in downtown Memphis. Loucks’ lawyer has suggested that he acted in self-defense. Loucks served in Afghanistan from March 2009 to March 2010. Loucks' lawyer says he was honorably discharged with post-traumatic stress disorder.