The authorities on Thursday identified Ian David Long, 28, as the gunman in the mass shooting at the Borderline Bar & Grill in Thousand Oaks, Calif.
The police said Mr. Long killed 12 people in a late Wednesday night attack on the bar, which was crowded with people dancing to country music. He appeared to have died from a self-inflicted gunshot wound after exchanging fire with officers at the scene, the Ventura County Sheriff’s Office said.
Here is what we know about the suspect:
• Mr. Long, of Newbury Park, Calif., had served in the United States Marine Corps.
• Sheriff Geoff Dean said deputies had several interactions with Mr. Long over the last few years. One of the encounters involved a reported disturbance at his home in April that prompted mental health specialists to talk to him.
• The specialists who spoke with Mr. Long discussed his military service with him and whether he had suffered from post-traumatic stress disorder. They determined that he was not an immediate danger to himself or others and that he could not be involuntarily taken to a mental hospital.
• Sheriff Dean said that Mr. Long was the victim in a January 2015 fight at a different bar in Thousand Oaks.
• After the Wednesday night shooting, the authorities recovered a handgun inside the Borderline Bar & Grill, a Glock 21 .45-caliber handgun, which they believe Mr. Long used in the attack. The firearm had been outfitted with an extended magazine to hold more bullets than a typical handgun. It had been purchased legally, Sheriff Dean said.
• Mr. Long first shot a security guard outside the bar, went inside and then shot more security personnel and employees before opening fire on patrons. Read here for the latest developments on the Thousand Oaks shooting.
This is a developing news story. Check back for updates.