Thousand Oaks, CA - The gunman who shot and killed 12 people at a country music bar in a Los Angeles suburb was a former military machine gunner who was interviewed by mental health specialists earlier this year after a neighbor reported a disturbance.

Ian David Long, 28, served in the Marines for nearly five years, including a seven-month tour in Afghanistan, according to the Pentagon. He left as a corporal in March 2013 and recently was living with his mother in Thousand Oaks.

In April, a neighbor called authorities to report loud noises coming from Long’s house. Deputies found Long “was somewhat irate, acting a little irrationally” and called in a mental health specialist, Ventura County Sheriff Geoff Dean said. That specialist assessed Long but concluded he couldn’t be involuntarily committed for psychiatric observation.