The gunman, identified by authorities as Ian David Long (28) was found dead in the office of the Borderline Bar and Grill, located in Thousand Oaks, a suburb about 40 miles from Los Angeles after the incident on Wednesday night, apparently having shot himself.
Ventura County Sheriff Geoff Dean told a news conference on Thursday morning that Long was a Marine Corps veteran of Afghanistan and had apparently fired at random with a .45-caliber Glock handgun with an extra-capacity magazine. There was no known motive, he said.
"Obviously he had something going on in his head that would cause him to do something like this," Dean said. "Obviously he had some sort of issues."
Dean said authorities were waiting for a search warrant for Long's home in Newbury Park, about 6km from the bar.
The bar shooting was the latest mass killing in the United States and was sure to revive the debate on gun control. Less than two weeks ago 11 worshippers at a synagogue in Pittsburgh were killed by a man shouting "All Jews must die."
The Borderline is popular with university students and on Wednesday night hosted College Country Night. California Lutheran University, located about 5 miles from the bar, canceled classes on Thursday while Pepperdine University, about 20 miles away, planned a prayer service.
Bar patron Cole Knapp (19) told Reuters he saw the gunman walk in and stop at the counter, apparently paying a cover charge. Then Knapp heard gunfire and saw a young woman at the counter shot repeatedly.
"It took a couple of seconds for people to realize what was going on and once that happened it was just utter chaos," he said.
Knapp said he first helped people hide behind a pool table and then fled to the bar's outdoor smoking patio, where people were unaware of the shooting.
'I'M JUST REELING'
Once outside Knapp and a friend helped carry a gunshot victim to an ambulance.
"I'm just reeling, riding on adrenaline right now," he said. "It's just kind of unbelievable that somebody would want to come to a place I care about and hurt people that I care about."
Ventura County Sheriff's Office Sergeant Ron Helus, a 29-year veteran, was one of the first law enforcement officials to reach the Borderline at about 11.30pm. He was shot in the bar and died at a hospital, Dean said.
A statement from the sheriff’s office said there would be a procession in honor of Helus on Thursday morning. "Ron's selfless, heroic actions will never be forgotten," the statement read. He is survived by a wife and son.
Asked what the scene inside the bar was like, Dean said, "Like ... hell." Earlier he had described it as "a horrific scene in there. There is blood everywhere and the suspect is part of that."
Long allegedly first shot a security guard outside the bar, stepped inside and resumed shooting, Dean said. Witnesses said Long used smoke bombs to create confusion but Dean could not confirm that.
Dean, who was speaking on his last day before retirement, said he had been told 150 to 200 people were in the Borderline at the time. "It could have been much, much worse," he said.
Dean estimated 10 to 15 people, including one with a gunshot wound, had gone to local hospitals. He said he believed their injuries were minor, and that most of them were likely injured as they escaped, some by breaking windows.
HISTORY WITH POLICE
Dean told reporters that officers had gone to Long's home in April in response to a disturbance call and found him to be agitated. Mental health specialists talked with Long and determined that no further action was necessary.
About 60 people, many of them crying, gathered at a teen center in Thousand Oaks waiting to learn if their loved ones were among the dead.
"They're just hoping against all odds in a sense," Thousand Oaks City Councilman Rob McCoy said at a news conference outside the teen center. "The longer they wait it appears to be inevitable to many of them and you just hug them."
President Donald Trump, who has resisted a surge in calls for tougher gun control measures since 17 students and staff were shot dead at Stoneman Douglas High School in Florida earlier this year, ordered flags to be flown at half-staff at public buildings and grounds.
U.S. Representative Jerry Nadler, the top Democrat on the House Judiciary Committee, said lawmakers would get to work on legislation including universal background checks when the House convenes in January with a Democratic majority.
"We must find a way to stop the senseless and many times preventable killings that are robbing our country of innocent lives," he said on Twitter.
Thousand Oaks, a leafy, sprawling suburb, was named the third safest city in the United States for 2018 by the website Niche.
"I've learned it doesn't matter what community you're in," Dean told reporters when asked if he was surprised this happened in Thousand Oaks. "It doesn’t matter how safe your community is. It can happen anywhere."
