Navy Yard Gunman Had Been 'Hearing Voices' And he had a 'pattern of misbehavior' in the military By Kevin Spak, Newser Staff Posted Sep 17, 2013 7:58 AM CDT Updated Sep 17, 2013 7:59 AM CDT 131 comments Comments This undated photo provided by Kristi Kinard Suthamtewakul shows Aaron Alexis in Fort Worth, Texas. (AP Photo/Kristi Kinard Suthamtewakul) (Newser) – Aaron Alexis, who is now believed to have been the only shooter behind yesterday's Navy Yard massacre, suffered from serious mental issues, including paranoia and a sleep disorder, and had been hearing voices in his head, sources tell the AP. Alexis also suffered from PTSD, his father told investigators, according to the New York Times. He had been disturbed by the 9/11 attacks, his father explained; he was an "active participant" in rescue efforts in New York. Alexis had been getting treatment for these issues from the Veterans Administration, but the Navy hadn't declared him mentally unfit. Had it done so, he'd have lost his security clearance. Other details trickling out include: Alexis was kicked out of the Navy Reserve for a "pattern of misbehavior," one Navy official tells the Washington Post. He was given a "general discharge," which is seen as a reprimand. That misconduct included a 2010 incident in which he fired a gun into his floor. His downstairs neighbor told police she felt threatened, because Alexis had previously complained about the noise. Alexis said the gun went off accidentally. The incident got him evicted. Alexis was also arrested in 2008 on a disorderly conduct charge and spent two nights in jail. None of his arrests ever led to a conviction. Authorities say there's no evidence Alexis had any ideological motive, or any personal grudge against anyone at the Navy Yard. A friend does tell CNN that Alexis was upset about his pay in his contracting job, believing he hadn't been compensated properly for a months-long assignment in Japan. Alexis "had a gun at all times," according to Oui Suthamtewakul, the owner of the Thai restaurant where Alexis worked in exchange for free rent. Suthamtewakul considered Alexis a friend, and described him as "a 13-year-old stuck in a 34-year-old's body." He was a heavy drinker, and was forward with women. Suthamtewakul also reveals that Alexis shot a bullet through the wall of his room last summer. "You're gonna kill me," the landlord told him. Alexis apologized. For more on Alexis, click here.