The city of Thousands Oaks, California, remains in mourning after a former marine opened fire at a country music bar Wednesday night, killing 12 people, mostly students. It was the deadliest mass shooting in the United States since the Parkland, Florida, school shooting in February. Police have identified the gunman as 28-year-old Ian David Long, a Marine veteran who had deployed to Afghanistan and had a history of mental health issues, including possible PTSD. Police said Long set off smoke grenades inside the bar before opening fire using a Glock .45-caliber handgun equipped with an extended ammunition magazine. Long also died inside the bar. Long reportedly frequented the Borderline Bar & Grill before the shooting and had had multiple interactions with local authorities. Earlier this year, he was evaluated by mental health professionals after police responded to a disturbance at his home, where he lived with his mother—but he was cleared by the specialists. On Thursday, Ventura County Sheriff Geoff Dean discussed Long’s previous encounters with law enforcement.

Sheriff Geoff Dean: “We’ve had several contacts with Mr. Long over the years, minor events such as traffic collision. He was a victim of a battery at a local bar in 2015. In April of this year, deputies were called to his house for a subject disturbing. They went to their house. They talked to him. He was somewhat irate, acting a little irrationally. They called out our crisis intervention team, our mental health specialist, who met with him, talked to him and cleared him, didn’t feel that he was qualified to be taken under 5150, and he was left at that scene last April.”

We’ll have more on the shooting after headlines.