The trial of the ex-Marine accused of murdering American Sniper Chris Kyle begins today, and the much-watched case is likely to last about two weeks, NBC News reports. Jurors in Stephenville, Texas, will receive 24-hour-a-day security as they deliberate over what looks to be the trial's key question: whether the accused man, 27-year-old Eddie Ray Routh, is not guilty of murder by reason of insanity. Following his arrest, Routh, whose lawyers say had post-traumatic stress disorder, told authorities that "tons of people (were) eating my soul." Referring to Kyle, he said, "I knew if I didn't take out his soul, he would take my soul next." In a 911 call after the shooting of Kyle and Kyle's friend Chad Littlefield, Routh's sister called her brother "f---ing psychotic," CNN reports.
As for prosecutors, they plan to argue that Routh was using alcohol and marijuana the day of the murders; they hold that Routh's past has been rife with "self-intoxication" involving a variety of drugs, WFAA reports. Prosecutors will also argue that Routh used a knife to threaten his girlfriend on the day of the incident. NBC notes three possible outcomes for the case: life in prison, if Routh is found guilty of capital murder; 20 years in prison, if he's convicted of second-degree murder; or a not-guilty verdict if jurors believe he was legally insane. He would then likely spend the rest of his days in a mental health facility. Such a verdict carries weighty implications for others with PTSD: "It's such a big case that it's going to make us look like we're crazy, and we're not ... We don't want the civilian world to be intimidated by us, to be scared or to wait for us to come in and shoot up people," says a former soldier. "I feel like that's what this is going to do." (Read more Chris Kyle stories.)