A gunman opened fire in a crowded Southern California bar popular with college students, killing 12 people, including a sheriff’s deputy, police said yesterday.
The gunman, identified by authorities as Ian David Long, 28, was also found dead on Wednesday night in the office of the Borderline Bar and Grill, located in Thousand Oaks, a suburb about 40 miles from Los Angeles, 
He had apparently having shot himself.
Ventura County Sheriff Geoff Dean told a news conference yesterday morning that Long was a Marine Corps veteran and had apparently fired at random with a.45-calibre Glock handgun with an extra-capacity magazine.
There was no known motive.
“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.”
He said authorities were obtaining a search warrant for Long’s home.
The Borderline is popular with university students and on Wednesday night was hosting College Country Night.
California Lutheran University, located about five miles from the bar, cancelled classes yesterday while Pepperdine University, about 20 miles away, planned a prayer service.
One of the victims was Sheriff’s Sergeant Ron Helus, a 29-year veteran of the department who died at a hospital, Dean said.
Helus and a California Highway Patrol officer were the first to arrive at the bar and went inside just before 11.30pm.
A statement from the sheriff’s office said there would be a procession in honour of Helus, who leaves behind a wife and son.
“Ron’s selfless, heroic actions will never be forgotten,” the statement read.
Asked what the scene inside the bar was like, Dean said: “Like ... hell.”
Earlier, the sheriff had described it as “a horrific scene in there. There is blood everywhere and the suspect is part of that”.
Long first shot a security guard outside the bar, stepped inside and resumed shooting, Dean said.
Witnesses said that Long had used smoke bombs to create confusion, but Dean said that had not been confirmed.
Dean, speaking on his last day before retirement, said he had been told that 150 to 200 people were in the Borderline at the time and that “it could have been much, much worse”.
Dean estimated 10 to 15 people, including one with a gunshot wound, had gone to hospitals.
He said he thought their injuries were minor, and that most of them were likely injured as they escaped, some by breaking windows.
Dean told reporters that officers had gone to Long’s home in April in response to a disturbance call and had found him to be agitated.
Mental health specialists talked with Long and determined that no further action was necessary.
Family members of possible victims or survivors of the shooting gathered at a teen centre in Thousand Oaks for news of loved ones.
A visibly distraught man was seen entering the building.
President Donald Trump, who has resisted a surge in calls for tougher gun controls since 17 students 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.
The Borderline massacre was the fourth mass shooting in the United States in less than two weeks.
The others included two women killed at a yoga class in Tallahassee, Florida, two people shot at a grocery in Jeffersontown, Kentucky, and 11 worshippers at a synagogue in Pittsburgh killed by a man shouting “All Jews must die.”
Last year, a country music festival in Las Vegas was the scene of the worst mass shooting in modern US history.
A gunman shooting from the 32nd floor of a hotel and casino with high power weapons killed 58 people.
Jerry Nadler, the top Democrat on the House Judiciary Committee, said that lawmakers would get to work on legislation including universal background checks when the House of Representatives 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.”
“He had perfect form,” bar patron Teylor Whittler told Fox News. “He looked like he knew what he was doing, he had practised.”