MARINE CORPS BASE CAMP PENDLETON, Calif. -- Post-traumatic stress disorder coupled with a troubled childhood -- compounded by threats from the victim -- caused Gunnery Sgt. Archie O-Neil to murder Kimberly O-Neal Feb. 29, 2004, defense counselors said Tuesday.After almost two weeks of testimony in court-martial proceedings here, the panel charged with deciding O-Neil-s fate finally heard from the defense.In an impassioned opening statement June 14, defense co-counsel Maj. Leon Francis said they would tell "the rest of the story" to the seven-member panel. Francis said the government had "presented very little of the story" and that defense lawyers would fill in the holes with "the why and how" surrounding the O-Neal murder. Francis took the jury back in time, detailing the O-Neil-s childhood in a poor Houston neighborhood. O-Neil-s father abandoned the defendant and his family when he was 7, Francis said, adding that O-Neil was sexually molested as a child. O-Neil wiped his eyes while Francis delivered the opening remarks.The defense team-s first witness, Navy Lt. Cmdr. Gerald Donovan, a psychiatrist, diagnosed O-Neil with PTSD and a personality disorder after his arrest March 1, 2004, in Kuwait and return to the U.S. O-Neil previously was deployed to Iraq during the early stages of Operation Iraqi Freedom. Abused children are more susceptible to PTSD if exposed to trauma -- such as combat -- later in life, Donovan testified. O-Neil-s wife, Monique O-Neil, took the stand next. The couple has been married for 13 years and has a 9-year-old son.Monique O-Neil testified it was "like Dr. Jekyll and Mr. Hyde" when her husband returned from Iraq. She described him as "very emotional" and "totally different." She added that her husband never felt safe after he returned -- and carried a gun with him everywhere he went, including restaurants.The defense is arguing the murder was an act of passion in the heat of moment with "no design, no plan, no premeditation," Francis said. He added "that PSTD . . . is why he had a weapon on him, not because he intended to shoot and kill Kim O-Neal." The defense claims O-Neal wanted the gunnery sergeant to leave his wife. Francis said she told the defendant, "I-m going to kill that bitch. I-m going to kill that bastard son." Fearful and angry, the defense claims, O-Neil then fired 13 rounds with a .45-caliber pistol, hitting O-Neal 11 times.Paramedics pronounced her dead at the scene. The murder weapon hasn-t been found. Prosecutors speculate that O-Neil, who left for the Middle East hours after the shooting, disposed of the weapon after arriving in Kuwait. Monique O-Neil, also from Texas, calmly, coherently answered attorneys- questions with a slight drawl.A tall, soft-spoken woman, she often gazed at her husband while on the stand. In response to questions from the defense, she testified that O-Neal once had attempted to hit her with her car. She also said the victim often sat in her car outside Monique O-Neil-s workplace and stared through the window. On cross-examination, Capt. Ryan Manning asked her why she never called the police about O-Neal-s behavior. "I didn-t want to, because it was just my word against hers," she said.The two couples met when the O-Neils bought a car from Kimberly and her husband, Gregory O-Neal. Monique O-Neil said the victim later became mad over a work relationship between the victim-s husband and Monique O-Neil.