"He was hard-working, he was totally committed, he gave his all and, tonight, as I told his wife, he died a hero", Dean said at a press conference early Wednesday.
Teylor Whittler told "Fox & Friends" she was at the country bar celebrating a friend's 21st birthday when the shooting occurred.
A man and his stepfather interviewed by ABC7 Eyewitness News said they heard about a dozen shots before they were able to flee out the front door. "There was an exit right next to me, so I went through that".
The shooter reportedly stormed into the venue wearing a black trench coat, armed with smoke grenades and a firearm with a high-capacity magazine.
A friend, Sgt. Eric Buschow, said Helus took on some of the toughest assignments, was on the SWAT team for much of his career and worked in narcotics and investigations.
It was the latest mass shooting to rock the United States, six days after the death of two women at a yoga class in Tallahassee, Florida and 12 days after an anti-Semitic gunman entered a synagogue in Pittsburgh and killed 11 worshippers.
Dean said his department had several previous contacts with Long, a former US Marine, including a call to his home in April, when deputies found him acting irate and irrationally.
People "dog-piled on top of each other" trying to hide in silence, she said.
Numerous patrons were local students from nearby California Lutheran University, ages 19 to 25, attending "College Country Night".
"Hey, I gotta go handle a call".
Authorities have identified the gunman and the handgun he used to kill 12 people at a southern California bar.
The 23-year-old was a recent graduate of California Lutheran University, and "heroically saved lives in the incident", according to the university's president, Chris Kimball. "There was probably three or four", one young man told local television station KABC. But Sheriff Dean has since said that the gunman died at the scene.
Sarah Rose DeSon told ABC's "Good Morning America" that she saw the shooter draw his gun. People dropped to the floor and hid behind bar stools in stunned silence.
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 64 kilometres west of Los Angeles, just across the county line.
UPDATE 6:30 a.m.
A lone gunman opened fire late Wednesday night with a.45-caliber handgun in the packed bar in Thousand Oaks, California, on what was billed as "college night". The shooter fired upon the police officers when they entered the bar.
Jason Coffman displays a photo of his son Cody outside the Thousands Oaks Teene Center where he came hoping to find his son who was at the Borderline Bar and Grill in Thousand Oaks, Calif., Nov.8, 2018.