Residents stood in silent shock and grief outside a California bar on Thursday where a former US marine had burst in the night before and shot dead 12 people, including a police officer. But some made their feelings known by carrying signs.

“Gun control now” read one carried by Grace Fisher, who had come from her nearby home to the scene of the mass shooting to pay her respects. Late on Wednesday night, college country and western line-dancing night was taking place at the Borderline Bar and Grill when, according to law enforcement, Ian Long, 28, entered and wrought tragedy with a handgun.

Fisher, who was carrying her baby with her, came after hearing about the tragedy from a neighbor.

“I just couldn’t sit at home and be sad,” she said. “I had to get out and come hold my sign and say: we demand more.”

Other locals in this quiet Los Angeles suburb of Thousand Oaks stood as an impromptu and subdued citizens’ honor guard as the body of Ventura county sheriff’s deputy Ron Helus was taken from the hospital, where he had died just hours after being shot as he rushed the gunman. His remains were being transported to the medical examiner’s office. One man held up a sign saying, simply, “Hero Helus”.

Cody Coffman, a 22-year-old who hoped to join the army, was among the dead. His father described himself as “heartbroken”. Justin Meek, 23, a recent graduate from nearby California Lutheran University, was also killed. The university said Meek had “heroically saved lives in the incident”.

The streets became packed full of local residents as Helus’s body was transported from the hospital. They had brought American flags to wave, a poignant gesture on a grim day. No one had organized the gathering. It was a spontaneous coming-together by locals upset and scared at what had happened in their midst.

“I’m still kind of in shock,” said Hannah, a local resident who preferred not to make her full name public. She was also outraged. “These kind of shootings have been happening way too often.” But she was also comforted by the turnout of people to pay tribute.

“It’s the biggest thing I can remember,” she said. “It’s why I love living here and being from here. Everyone shows up for each other.”

Back outside the Borderline bar, where many of the patrons on Wednesday night had attended California Lutheran, Pepperdine and other nearby colleges, red-eyed students in university sweatshirts hugged each other and wept.

California Lutheran, just a 10-minute drive north of the bar, planned to hold a vigil for the victims on Thursday afternoon.

Classes were cancelled at the private liberal arts college, as students and staff came to terms with the shooting.

“Something like this is just really unheard of,” said Richard Hurst, an adjunct professor in geology at CLU. Hurst described a safe community in which crime was rare.

He said a number of students were consoling each other in the campus chapel. “There’s a lot of students literally just buckled over crying,” he said.

Coffman’s father, Jason Coffman, described the 22-year-old as having “love for everybody”. He said: “There was so many people that he touched and now are going to be just as heartbroken as I am. This is a heart that I’ll never get back.”

Cody was pronounced dead at the scene, his father said. He wanted to join the military.

“He was on his way to fulfilling his dream of serving the country,” Coffman said.

Earlier in the day Coffman had described his frantic efforts to trace his son. Coffman knew Cody was at the bar, and through a tracker on his phone could see that Cody’s phone remained there hours after the shooting.

Coffman said his last words to Cody before he left for Borderline were: “Son, I love you.”

“I cannot believe that it’s happened to my family,” Coffman said. “My life has changed now forever.”

Asked how he felt about the gunman Coffman declined to comment. “I feel sorry for his parents,” he said.

CLU said its community was “filled with sorrow” over the shooting.

It said: “Sadly, we have learned from the family that a recent graduate, Justin Meek, 23, is one of the precious lives cut short in this tragedy. Meek heroically saved lives in the incident. Cal Lutheran wraps its arms around the Meek family and other families, and around every member of this community of caring.”

Outside the bar, Grace Fisher continued: “You’re getting your kids ready for school every day and you worry about sending them – and that’s not OK. I’m tired of it. It’s never going to be normal for us to do everyday, normal things and fear for our lives.”

Julia Mcelvy woke up to the news there was a mass shooting and realised she knew the people there. “I just found out that three of my daughter’s friends are deceased,” she told the Guardian. “It’s too close to home.”

Like hundreds of others who live or work in Thousand Oaks, Mcelvy was personally touched by the massacre at Borderline Bar and Grill. She had to do something, and the line around the block at La Reina high school, people waiting hours in the sun and heavy Santa Ana winds to give blood, demonstrated that she was not alone.

“I work right up the street and as soon as I heard about the blood drive I asked my boss if I could leave and he said, ‘please do,’” she recounted. “I would have come anyway.”

An affluent, tree-lined town just under an hour’s drive from Los Angeles, Thousand Oaks has long been perceived as a safe place to live, work and learn. That perception has changed.

“I think people are getting more comfortable with committing acts like this,” Mcelvy said. “I think it’s happening more frequently”. One survivor of Wednesday’s shooting was also reportedly a survivor of the 2017 mass killing in Las Vegas.

Anna Lundsten, a senior at California Lutheran University, had friends at Borderline. She came out at 8am, and was still waiting six hours later, to donate blood.

“There were just messages going around saying what people could do, and someone suggested blood donations – and I can do that, so I came here,” she said. As she spoke, volunteers passed out bottles of water, sandwiches and slices of pizza.

That the blood bank was there at all, in the immediate vicinity of another mass shooting, happened to be a coincidence.

“We weren’t prepared for something like this to happen,” said Taylor Prenslow, an employee at Vitalant, a not-for-profit that runs a number of blood centers around the country. “We were already having this drive, it just happened by chance to be in this area,” she said.

Kayla Wagenhofer, a recent graduate of CLU, had been waiting five hours when she spoke to the Guardian. She said her boyfriend woke her up at 5am to tell her the news. Browsing the coverage, she saw photos of people she knew.

“It’s very heartbreaking for everyone involved,” Wagenhofer said. She stayed in the area after college because everybody was so friendly – because “it’s really nice to be here.” The small-town, neighborly vibe was still to be found on Wednesday, but there is no longer that feeling of comfort.

“It’s very traumatizing for the entire community,” she said. “It disrupts everyone’s feeling of safety.”