The Los Angeles Times reports the gunman who killed 12 people at a Thousand Oaks, California,  bar was a former U.S. Marine who may have been suffering from post-traumatic stress disorder. The Ventura County Sheriff identified the shooter as Ian David Long, 28, who lived near the bar where he threw smoke bombs and rained bullets on a crowd of more than a hundred people Wednesday night. Long was also found dead in the bar.

Sheriff Geoff Dean said his department had had several interactions with Long, including a call to his home in April for a complaint of disturbing the peace. Deputies at the time said Long was irate and acting irrationally, Dean said. They called in mental health professionals to evaluate him, and they concluded he did not need to be taken into custody.

Long was dressed in black when he burst into the Borderline Bar & Grill, a country-music-themed venue popular with college students. He drove his mother’s car to the bar and did not say anything before opening fire, a law enforcement official said.

The shooter was armed with a Glock 21 .45-caliber handgun with an extended magazine that he purchased legally in Simi Valley, Dean said. A source said he also had a “smoke device.”