Once again, President Donald Trump has ordered flags at half-staff "in a mark of solemn respect".
Police told the Los Angeles Times that at least 30 shots were fired and the paper reported that people had been hit. Witnesses said the shots sounded like they were coming from a semi-automatic weapon.
UPDATE A police officer was among 13 dead, including the gunman, at a shooting in a bar in Thousand Oaks, California.
Long used a handgun with an "extended magazine" on it, Dean said.
Dean said it did not appear as though Long was targeting specific people. He was identified as Sheriff's Sgt. Ron Helus, a 29-year veteran about a year from retiring.
Here's what we know about the late Wednesday shooting.
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. "And he was left at that scene last April". "He went in to save lives, to save other people", he added.
He said that there are at least "six victims including one deputy" who are still inside the bar.
The Ventura County Sheriff's Office announced that a procession will be held for Helus at 10:00 a.m. today.More news: Trump's media relationship frays more
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He is survived by his wife and adult son. "It saddens us all and tears at our emotions". "There's no way to describe this". He died a hero.
"Ron ... gave his all and tonight, he died a hero because he went in to save lives", Dean said.
No other victims were identified. "There is blood everywhere and the suspect is part of that, and I didn't want to get that close and disturb the scene and possibly disturb the investigation".
Witness John Hodge told ABC7 he saw the suspect throwing smoke grenades into the front of the restaurant after shooting a security guard.
The motive of the attack is not clear, the sheriff said, and authorities are looking at all possibilities, including it being terror-related. On Thursday morning, deputies were outside the house as they sought a warrant to conduct a thorough search of the property. "We believe he shot himself".
"He was a great man", Capt. Garo Kuredjian, the force's public Information officer, told "Good Morning America" Thursday.
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.
According to the bar's website, a "College Country" night was going on at the time of the shooting.
Thousand Oaks is in Ventura County, about 40 miles from downtown Los Angeles.