By the time it was over, 12 people were dead, and gunman Ian David Long was dead from an apparent self-inflicted gunshot wound. "There's a fence right there so I said: 'Everyone get over the fence as quickly as you can.' And I followed them over".
Image: The gunman was captured on a survivor's mobile phone. And I hope to God nobody sends me anymore prayers.
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, said on Twitter that he had been "fully briefed on the awful shooting in California".
A number of gunshots can be heard in the footage at the country music bar.
The city of about 130,000 people is consistently near the top of lists of the safest places in California.
Long's only other contact with authorities came after a traffic collision and after he alleged he was the victim of a violent encounter in 2015 at another bar in Thousand Oaks, the sheriff said.
She shook with sadness and rage as she gave reporters her message on Thursday, "No more guns".
"I heard what I thought was a balloon pop", she told CNN.
The retired substitute teacher also took aim at the pro-gun National Rifle Association while recalling the 2012 Sandy Hook Elementary School massacre that killed 20 kids, saying: 'If mowing down 5-year-olds at Sandy Hook didn't make an impression, nothing will. Investigators have not commented on a motive for the shooting, or whether mental illness played a role.
Witnesses said he wore something like a ski mask as he opened fire in the packed club at around 11.20pm on Wednesday evening.