Ron Helus, a Ventura county sheriff's sergeant, was among those killed at the Borderline Bar and Grill, about 40 miles west of Los Angeles.
"They ran out of the back doors, they broke windows". "They would go fishing up in the Sierras [Nevada mountains] together".
The first post office in the area was built in 1875, and a small outpost there became a stop on the stagecoach route between Los Angeles and San Francisco, according to the city of Thousand Oaks' website.
"He had flawless form", bar patron Teylor Whittler told Fox News.
"It looked like he knew what he was doing", Whitler told KABC-TV.
Authorities so far had no indication of a motive, or of any connection to terrorism.
Officers arrived on the scene 2 to 3 minutes after the initial call to law enforcement as shots continued to ring out, Dean said.More news: Meg Ryan announces engagement to John Mellencamp
As they entered through the front door, Helus was struck by bullets, Dean said.
The extended magazine Long allegedly used can not be legally purchased in California under a 2000 law.
"He was raving hell in the house, you know, kicking holes in the walls and stuff and one of the neighbors was concerned and called the police", Richard Berge, who lived one block away from the home, told Reuters.
"Here are my words: I want gun control", said Susan Schmidt-Orfanos, her voice shaking with grief and rage.
As shots were heard at a bar in a suburb of Thousands Oaks, California, a "hero" sheriff's sergeant responded by putting himself in the chaos to try to "save lives" but was shot by the gunman.
Matt Wennerstron, a 20 year old college student and regular at the bar, said the shooter fired a short-barreled pistol that apparently had a 10-15 round magazine.
"I've learned it doesn't matter what community you're in", Dean said.
He said he and others smashed their way out of the bar onto a balcony and then jumped down to safety.More news: Star Wars 'Rogue One' Prequel Series Coming to Disney Streaming Service
He said he had friends who were unaccounted for.
"I see that girl every single time I'm there", witness Holden Harrah told CNN, fighting back tears.
"We didn't take it seriously at first. because it sounded like firecrackers and everyone just dropped down to the floor". "He really liked it", said one woman who has been friends with Long for five years and does not want her name made public. Earlier he had described it as "a horrific scene in there".
Long was "the victim of a battery" at a bar in Thousand Oaks in January 2015, Dean said.
In April this year, deputies were called to his house for a disturbance and found him "acting a little irrationally". He and his then-wife said they had no children and owned no property.
The assailant, identified as Ian David Long, a troubled former machine gunner who served a tour in Afghanistan, died of a self-inflicted gunshot wound.
Long was armed with a Glock 21, a.45-caliber pistol created to hold 10 rounds plus one in the chamber, according to the sheriff.
The witness, who escaped unharmed with his stepson, said he saw the gunman shoot multiple people. According to locals, Borderline Bar & Grill was a gathering place for people who loved country music.More news: Eden Hazard Starts - Chelsea Team vs BATE Borisov Confirmed
"Our thoughts and prayers are obviously with the people that it happened to", defensive coordinator Wade Phillips said. He was dead when police arrived on the scene, Ventura County Sheriff Geoff Dean said.