Matt Wennerstrom said he instinctively pulled people behind a pool table, and he and friends shielded women with their bodies after hearing the shots.
It was "college night" at the bar, and many students were there to learn the country two-step.
The sheriff's department and the wider community are mourning the "hero" officer today, who was one of the 12 people killed in the mass shooting in Southern California. He was later found dead at or near an office in the business.
"Unfortunately our young people, people at nightclubs, have learned that this may happen, and they think about that", Ventura County Sheriff Geoff Dean said. Dean said Helus undoubtedly saved lives by going in to confront the gunman. The gun had a special device that permitted it to hold more bullets than usual.
Dean said the shooter reportedly shot at employees and security before turning on the crowd. I was blessed to know you ever since you were 5.
The shooting at Borderline marks the 307th mass shooting in the USA this year, according to the Gun Violence Archive's records.
It was the nation's deadliest such attack since 17 students and teachers were killed at a Parkland, Florida, high school nine months ago.
The 23-year-old, who was a recent graduate of California Lutheran University, worked at the Borderline Bar and organized the college night event.
Cole Knapp, a freshman at Moorpark College, said he was inside the bar when the shooting began but thought at first that it was "just someone with an M-80, just kind of playing a prank". When the gunman burst in, her friend, Cody Coffman, yelled for her to get down.
He said he spoke to his son just before he went to the bar Wednesday night.
Ventura County Sheriff's Office Capt. Garo Kuredjian said at a news conference early Thursday that the wounded sheriff's deputy was taken to a hospital.
"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.
Neighbor Tom Hanson said Long lived in the home with his mother.
Video from the scene accessed by The Associated Press is punctuated by loud sounds of several rounds of gunfire.
"Only him and I know how I love, how much I miss him", he said. The deputies called in mental health specialists.
Long had no criminal record.
President Donald Trump was briefed on the shooting and praised law enforcement officers for their response. Active law enforcement incident.
The U.S. Marine Corps issued a statement extending "its deepest condolences to the families of the victims in this senseless tragedy".
The top Democrat on the House Judiciary Committee, Jerry Nadler of NY, said lawmakers would start crafting a gun-control bill when the House convenes with a Democratic majority in early January. I want gun control.
"We must find a way to stop the senseless, and many times preventable killings that are robbing our country of innocent lives", Nadler tweeted.
Thousand Oaks is a wealthy area about 60 kilometers northwest of Los Angeles.
Thousand Oaks, with a population of about 127,000, is a leafy, sprawling suburb named the third safest city in the United States for 2018 by the Niche research company.
He loved spending time with his son fishing in the Sierras, friend and colleague Sgt. Eric Buschow said. "It doesn't matter how safe your community is". Caty Weaver was the editor.