THOUSAND OAKS (CBSLA) – FBI data suggests that Thousand Oaks is the third-safest city in the country. It’s now the location of the latest mass shooting.

The Southern California city, situated 40 miles northwest of Los Angeles, is an upscale community in the foothills of the Santa Monica Mountains with a population of nearly 130,000 and a median household income of $101,045. Thousand Oaks has more than 15,000 acres of publicly owned natural, open space.

The Ventura County community was flipped upside down late Wednesday night – college country music night at Borderline Bar & Grill where nearly 200 people were trapped inside when a gunman armed with a Glock .45 caliber handgun opened fire. He shot a security guard at the front entrance then deployed smoke bombs inside before shooting at random.

Inside the bar, 12 people were killed and panicked patrons scrambled to escape. Some jumped through windows while others hid in restrooms.

A witness who was inside the bar during the shooting said she heard “very, very loud gunshots.”

“There were people in the middle dancing and just hanging out and having a good time and you hear that and you just know something’s up,” Erika Sigman said.

Of the 12 victims was Ventura County Sheriff’s Sgt. Ron Helus, who immediately charged inside to confront the gunman. Helus’s heroics are being credited with saving lives.

“He was a hero before and he remains a hero now,” said Ventura County Sheriff Union President Scott Peterson, who went to the academy with Helus some 30 years ago.

Helus, who is survived by his wife and son, was a 29-year veteran of the department who was set to retire next year.

“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 in to save lives, to save other people,” Ventura County Sheriff Geoff Dean said.

The Ventura County Sheriff’s Office said several of the patrons at Borderline were off-duty police officers who were all unarmed. When the gunfire began, officers helped shield some of the survivors.

The gunman has been identified as 28-year-old Ian David Long, a former Marine.

Violent crime is a rarity in Thousand Oaks with 123 incidents per 100,000 and annual property crimes of 1,298 per 100,000.

“In this community, it’s very hard for me to comprehend it because I’ve been here all my life and to think that – I’ve never experienced it, I’ve just never experienced it,” Sigman said.

The shooting has left many in the community understandably stunned, including Ventura County Sheriff’s Office Sgt. Eric Buchow.

“I don’t even know how to describe it,” Sgt. Eric Buchow told CBS2. “It’s quiet here. This kind of thing just doesn’t happen. To my understanding, I’ve lived in Thousand Oaks, I grew up here, we’ve never had anything of this magnitude.”

“It’s a tough night for everybody here, there is no doubt,” Sgt. Buchow continued. “There are a lot of people whose lives have changed tonight. And, it hits home. Not just the deputy but all of the victims. Our hearts go out to families and loved ones of everybody involved in this. This is going to have a lasting impact on the community there’s no doubt.”