What we know about the bar shooting
Sgt. Ron Helus was shot several times during an exchange of gunfire with the gunman, Ventura County Sheriff Geoff Dean said.
The shooter, Ian David Long, walked up to the Borderline Bar & Grill and shot a security guard standing outside, the sheriff said.
Long, who was wearing a black sweater, entered the bar, turned right and shot other security guards and employees, Dean said.
He then opened fire inside the bar, the sheriff said.
Long also exchanged gunfire with Helus and a California Highway Patrol officer when the entered the bar, he said.
It is unclear if Long reloaded his weapon during the shooting.
"We don't have any other details to confirm an exact chronology about what happened. We'll provide that to you as we bring all our witness statements together and we feel more comfortable about talking about that," Dean said. "We have no idea what the motive was at this point."
When asked how many people were inside the Borderline Bar & Grill at the time gunfire broke out on Wednesday night, Ventura County Sheriff’s Office Capt. Garo Kuredjian said, “I would say hundreds, but I can’t confirm the exact number.”
The bar was hosting a weekly college country night event, according to its website.
As news emerged of the incident, people began to gather outside the bar, located just outside Los Angeles, in a desperate bid to check on their friends.
"I heard that the gunman started shooting at the front desk and then from there I'm not sure. Friends I have that are in there reported that students are hiding in the attics and bathrooms and stuff like that," one bystander said.
Holden Harrah, who witnessed the shooting at the Borderline Bar & Grill, said he was inside the bar with friends, something he does every week.
"I’ve been coming there for about six months. (It's) just a place you go to hang out with friends, just have fun as young adults," he told CNN by phone.
"A gentleman, who walked in through the front door, shot the girl that was right behind the counter," he added.
Ventura County Sheriff Geoff Dean has described the scene of the bar shooting in Thousand Oaks, California as "horrific."
"It’s a horrific scene in there, 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," he said, adding that the motive is still unclear.
Dean said investigators had not found any type of assault rifle within the bar.
"Right now as far as we know there was only one handgun, but that could certainly change as we do a more thorough search of the building."
Thousand Oaks mayor Andy Fox told CNN he was informed of the shooting at the Borderline Bar & Grill around midnight, adding law enforcement responded quickly.
"It’s my understanding they went in and neutralized the shooter (and) they identified a number of causalities. I don’t know the condition of the victims but my understanding is there are a number (of) wounded included a local deputy … all of the victims have been transported to hospitals," Fox told CNN on the phone.
He added that Thousand Oaks "is considered one of the safest cities in the country."
"We are consistently ranked one of the highest with respect to the lowest crime rate per capita, we’re proud of that," Fox said.
"The reality is that these types of incidents can happen really at any place, at any time, even in communities that are considered extremely safe," he added.
The bar itself
Borderline Bar & Grill in Thousand Oaks is a western-themed establishment known to regularly host country, salsa and swing dancing nights.
According to its website, the venue was hosting a college country night between 9 p.m. and 2 a.m. on Wednesday night when the shooting occurred.
The bar is a few miles from California Lutheran University and is a popular spot for students. Some students from both California Lutheran University and nearby Pepperdine University are thought to have been present at the event on Wednesday night.
Madeleine Carr, news editor at student newspaper the Pepperdine Graphic, told CNN on the phone, that she was aware of freshman students who had planned outings.
"I was going to go with them tonight but decided not to because of homework but it is a popular place to go because it's local and we do have a lot of people from the south -- it's line dancing it attracts them," she said.
"We've been texting as much as we can -- it's hard. We are still trying to reach most of the girls but the people we know got out. A lot of them do live nearby in Thousand Oaks so a lot of them did get to a students house," she added.
Madeline Carr, news editor at the student paper the Pepperdine Graphic, knew some of those who were inside the Borderline Bar & Grill when the shooting started.
She told CNN the bar opens up to anyone over the age of 18 on Wednesdays and described it as a "fun spot for dancing."
"Pepperdine's a pretty small community, a pretty sheltered community ... so it's one of these events that it's hard to rationalize it happening here," she continued.
Carr said that it was heartbreaking to hear that Sgt. Ron Helus, one of the first police officers to respond to the mass shooting, had died.
"You hear about these shootings and the people that are the first responders and that really lay down their lives to help other people… I think it’s remarkable what these people do and I can’t say enough for individuals like him," she said.
"It’s heartbreaking and I know that the community will definitely be rallying together for the sergeant and the other individuals."
Twelve people, including a police officer, were killed after a gunman forced his way into the Borderline Bar & Grill and opened fire on Wednesday night, Sheriff Geoff Dean told reporters moments ago. The suspected gunman was also found dead at the scene. Up to 12 other people are injured.
A Ventura County sheriff’s deputy is among those killed in the Borderline Bar & Grill shooting.
Sgt. Ron Helus had been on the force for 29 years and was one of the first officers on the scene in response to 911 calls of shots fired. He was looking to retire in the "next year or so," Sheriff Geoff Dean told reporters.
The sergeant died in hospital, Dean added.
"Ron was a hardworking dedicated sheriff's sergeant. He was totally committed, he gave his all and tonight, as I told his wife, he died a hero; he went into save lives, to save other people," Dean said, his voice breaking with emotion.
Again, my heart breaks for the community, and our nation. All of the victims and survivors and heroes. We are making progress, yet things like this keep happening. I hope this California bar massacre can open the eyes of more people. I hope it disturbs more people. Just because it didn’t happen in your town, or involve anyone you know, doesn’t mean it didn’t happen and you should have the luxury of disregarding its disgusting place in American history. We all mourn with the victims and their families.