THOUSAND OAKS (CBSLA) – As “Amazing Grace” filled the Fred Kavli Theatre in Thousand Oaks, thousands held up candles to honor those lost in the mass shooting at Borderline Bar & Grill less than 24 hours earlier.

Twelve people, including a Ventura County sheriff’s sergeant, were killed when a gunman opened fire inside the bar before turning the gun on himself.

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Mayor Rob McCoy led the vigil, Ventura County Sheriff Geoff Dean received a standing ovation and various religious leaders spoke to comfort those who were inside and outside.

Mariah Piasecki said her of two best friends, Blake Dingman and Jake Dunham, died in the shooting. She was supposed to go out with them to the bar for a college country music night

“Jake, always a crazy one. You had a bad idea and everyone wasn’t for it, he’d be the one person for it and he’d tell you just to do it. Same with Blake, they were both the crazy ones out of the group,” Piasecki said. “Always going to the desert together, sitting by fires, just talking about everything. Those were, honestly, the best two people I’ve ever met.”

[Reporter: What did they mean to you, Mariah?]

“Everything,” she said.

Josh Kelly is the head DJ at borderline. He wasn’t working Wednesday night, but he spoke about his friend, Justin Meek.

Meek was the head promoter and security guard at Borderline. He had just graduated from California Lutheran University.

“He was one of the best I’ve ever met. The kid, he just — he would take a bullet for you. That’s who he was. He was only going to be there a couple more months, he had a short gig at Disney then he was going for the Coast Guard,” Kelly said. “So he had his life ahead of him, right around the corner. He’s not with us anymore because he was protecting our brothers and sisters.”

Mayor McCoy estimated about 2,000 people attended the vigil. He said he hoped it was the first step in healing for the community.

Another victim, Sean Adler, worked as a bouncer. He recently opened a coffee shop in Simi Valley, where friends gathered Thursday night to remember him.

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Hundreds of people left candles and flowers and shared memories of the father of two who owned Rivalry Roasters coffee shop.

Adler was working at Borderline when he was killed. He was remembered as a “dynamic” person.

“He was just real passionate about his business, his life, his kids,” said Russ Austin.

To get a full picture of who Adler was, you have to look at how many lives he impacted.

“You see all these people out here, these are all the people that he has done good for,” Chris Kurtis said.

About 200 people gathered around the coffee shop that Adler had opened just three months ago, specializing in exotic roast.

“He seemed like a dynamic individual,” one woman said.

Adler did it all: He was a strength conditioning coach at a local high school, loved martial arts and spent years as a bouncer at Borderline.

At home, he was a husband and father of two boys, 10- and 16-years-old.

“I’m numb right now…Sean’s done so much to help this community,” Kurtis said.

He did his final good deed as stories come out of how Adler tried to protect people inside of the bar when gunshots rang out.

“From what we hear, he engaged him first, and I know Sean, he tried his best. No ifs ands or buts about it – that is him,” Kurtis said.

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Another vigil is planned for Friday at 8 p.m. at Rivalry Roasters in Simi Valley. Adler’s mother and sister are expected to attend.