“Confirmed 4 deceased at scene, inc. the shooter,” the Orange County Sheriff said on social media. “6 transported to hospitals, 5 reported (with) gunshot wounds.
“Officer-involved shooting occurred during the incident. No deputies injured.”
The shooting took place at the Cook’s Corner bar, a venue popular with bikers, around 45 miles (72 kilometers) southeast of Los Angeles.
The Orange County Register, citing sources, said the incident was sparked by a domestic dispute.
The paper said the gunman was a former law enforcement officer.
One man interviewed by ABC7 said he had friends in the bar who were unscathed.
“They’re upset, of course. They were right next to the shooter. They said it’s an older man with a gray beard,” he told the news outlet.