Kuredjian said it has been "quite some time" since there was a shooting of any kind in Thousand Oaks, a city of about 130,000 people about 40 miles (64 kilometres) west of Los Angeles, just across the county line.
The suspect, who has not been identified, was found dead inside the bar, Dean said. Witnesses say people were dancing and having a good time when someone stormed in, and began firing.
"Ron was a hardworking, dedicated sheriff's sergeant", Dean said. A handgun was recovered at the scene, which Dean says has not been examined in detail yet.
Long served in the Marines from August 2008 until March 2013.
The shooting is the latest in a long list of mass shootings in the US.
Helus was immediately hit with multiple gunshots, Dean said.
The police were reportedly called to Ian's house back in April when his neighbors heard crashing noises from inside of the home the ex-Marine shared with his mom in Newbury. Deputies called the crisis intervention team, and mental health specialist who met with Long.
People comfort each other outside the scene of a shooting, November 8, 2018, in Thousand Oaks, California.
The Israeli Foreign Ministry said it was checking to see if any Israelis were among the victims.
Ventura County Sheriff's Office Sgt. Eric Buchow told the station there were "multiple fatalities" and the gunman was dead inside.
He is survived by his wife and adult son.
"Losing Ron, we go to the gym together and work out together", Dean said. "There's no way to describe this". It saddens us all and tears at our emotions. He died a hero. "He was totally committed, he gave his all, and tonight, as I told his wife, he died a hero". He said he regrets not staying in the bar to help other victims. Dean said there was "blood everywhere" inside the bar.
According to the sheriff, the gunman forced his way into the bar after shooting a security guard outside.
"Impossible to put any logic or sense to the senseless", Dean said during a news conference.
The motive of the attack is not clear, the sheriff said, and authorities are looking at all possibilities, including it being terror-related. They are still searching and investigating.
He said the gunman had apparently shot himself.
The police captain also did not know whether the gunman had been "neutralised" or not calling the situation "fluid".
The bar was holding its regular "College Country Nights" on Wednesday night when the gunman dressed in black opened fire inside the bar.