California bar gunman who killed 12 people identified as former US Marine

Related Story: 'Horrific' scene as gunman kills 12 at California bar student night

The hooded man who shot up a California bar and killed 12 people has been identified as Ian David Long, a former US Marine who served in Afghanistan and may have suffered PTSD.

Key points:

  • Survivors jumped out of windows to avoid being shot
  • Slain police sergeant remembered as a hero
  • Authorities are still trying to find a motive for the "tragic, senseless loss of life"

The 28-year-old veteran is suspected of carrying out the shooting at a bar in Thousand Oaks, and the dead included Sheriff's Sergeant Ron Helus, the first responder to the fatal attack.

Patrons at the bar screamed in fear, shouted "Get down!" and used barstools to smash second-floor windows and jump to safety as gunfire erupted at the Borderline Bar and Grill, a hangout popular with students from nearby California Lutheran University.

Ventura County Sheriff Geoff Dean said police believed Long then turned the gun on himself, bringing the death toll to 13.

There was no known motive, he said.

Ventura County Sheriff Geoff Dean speaks to a crowd of reporters.

One of the victims, 22-year-old Cody Coffman, has been identified by his father, Jason.

Of the injured, one other person suffered a gunshot wound and up to 15 others suffered minor injuries from jumping out windows and diving under tables.

Survivors left reeling

Cole Knapp, 19, said he helped patrons hide from the shooter

The bar was holding its regular "College Country Nights" on Wednesday night when the gunman dressed in black opened fire inside the bar.

Bar patron Cole Knapp, 19, told Reuters he saw the gunman walk in and stop at the counter, then he heard gunfire and saw a young woman at the counter shot repeatedly.

"It took a couple of seconds for people to realise what was going on and once that happened it was just utter chaos," he said.

Mr 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.

People sit on the ground wrapped in blankets after a mass shooting at a bar in California.

Once outside Mr 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."

Suspected killer deployed in Afghanistan

Sheriff Geoff Dean details what police know about shooter Ian David Long.

Long was a decorated Marine Corps machine gunner deployed in Afghanistan who had several prior brushes with law enforcement, police and Marine officials said.

He joined the Marines in 2008 and rose to the rank of corporal before leaving active service in 2013, Marine spokesman Joseph Butterfield wrote in an email.

He served in the war in Afghanistan for seven months, beginning in late 2010, and was awarded multiple ribbons, commendations and medals.

California mass shooting

He was interviewed by police at his home in April after an episode of agitated behaviour that they were told might be post-traumatic stress disorder.

Sheriff Geoff Dean said police had responded to a minor disturbance.

"He was somewhat irate, acting a little irrationally," Sheriff Dean said, but he said he was unaware of a PTSD or mental illness diagnosis.

"Obviously he had something going on in his head that would cause him to do something like this."

The police called in a team of mental health specialists who decided that Long did not qualify to be involuntarily detained for mental health evaluation under state law.

Sheriff Dean added Long obtained the murder weapon — a Glock 21 .45 calibre handgun — legally, but the weapon had an illegal magazine extension.

A neighbour, who would only identify himself by his last name, Mr Hanson, said Long lived with his mother.

"I mind my own business and they did theirs too," he said in a brief telephone interview.

A woman in the background added: "He was kind of a loner."

An American flag hung on the garage at Long's home on Thursday as law enforcement gathered outside preparing to search his home.

Helus hailed as a hero

Sheriff's Sergeant Ron Helus.

Friends are remembering the man who was killed trying to stop the shooting rampage as a "cop's cop" who didn't hesitate to run toward danger.

Colleagues of Sergeant Helus describe him as a friend and an exceptional man and officer.

"The fact that he was the first in the door doesn't surprise me at all," Sheriff's Sergeant Eric Buschow said.

"He's just one of those guys that wouldn't hesitate in a situation."

Helus was married with a grown son and took up fly-fishing a few years ago, Sergeant Buschow said.

"He was just a great guy, a gentle soul," he said.

"He would go to the ends of the Earth to find a suspect. Just an awesome investigator."

He said Sergeant Helus was on the SWAT team for much of his career and worked in narcotics and investigations.

Sheriff Geoff Dean, who choked back tears while talking about Sergeant Helus, said his friend had been talking to his wife when the shooting call came in.

"[He] said to her, 'Hey I got to go handle a call. I love you. I'll talk to you later,'" Sheriff Dean said.

Sheriff Dean called Sergeant Helus a "hero" and said he has no doubt he and a California Highway Patrol officer who also was the first to respond "saved lives by going in there and engaging with the suspect".

"He went in there to save people and paid the ultimate price," he said.

Latest mass shooting in US

The 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".

External Link: Tweet Trump California shooting

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 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.

One reporter asked the Sheriff what could be done to stem the flow of mass shootings in the United States.

"That's a pretty challenging question," Sheriff Dean said.

"If I knew the answer to that, I'd do something to stop it."

President Donald Trump has ordered that the US flag be flown at half-staff in respect for the victims of the shooting.

a woman puts her hand on another woman who is crying

Asked what the scene inside the bar was like, Sheriff Dean said, "Like … hell."

Speaking a day before his retirement, he described the shooting as a "tragic, senseless loss of life".