Even before a teenager strolled into the public library in Chico where police say he fatally shot two people on Monday afternoon, this building stood apart in the northern California community.

It is the only public library that serves the city of about 107,000 people, and most residents have some connection to it.

Chico residents describe their branch of the Butte county library as a treasured resource that provides story time for children and English learning conversation groups, and acts as a lifeline for those who otherwise lack internet access. It played a crucial role to fire survivors navigating the challenges of displacement after California’s deadliest wildfire hit the nearby towns of Paradise and Magalia in 2018.

The random act of violence on Monday in a sacred community space left two men dead and a child injured, and shattered the sense of safety in the city. For nearly a decade, Chico had been in close proximity to tragedy with years of deadly wildfires in the region and high-profile shootings in nearby towns.

But until this week, the city never faced this particular form of American violence. The community is still reeling, only just beginning to grapple with the long trail of damage.

“It’s unimaginable,” said John Wollam, a 35-year resident of the city. “I have family that lives in Vegas and they were there for the country music festival shooting. You never think something like this would never happen in our community.”

The tragedy began shortly after 5pm on Monday when police say Bradley Scott Sayer, an 18-year-old who had graduated from Chico high school just two weeks earlier, walked into the library an hour before the facility was set to close. It was a quiet time for the library, with most visitors having already come and gone, and less busy than it is other days of the week, the branch director, Kimberlee Wheeler, told the Guardian.

Sayer walked through the building and then returned to his car and grabbed a shotgun, Sid Patel, a field agent in the FBI’s Sacramento office, told reporters on Wednesday. He shot the first victim at the library’s entrance. Once inside, he fired multiple shots.

Jacob Cody Hull was in the library with his partner’s daughter, and died protecting her, said Wollam, who was a friend and neighbor to the 46-year-old.

Library staff were quick to respond, ushering patrons and families into locked workrooms, said Wheeler, who was off-site at the time of the shooting. She received a message from an employee informing her of what was happening.

“My staff was very courageous and level-headed and I’m in awe of them and their ability to maintain that,” Wheeler said.

Chico police dispatchers received multiple 911 calls where they could hear what sounded like screaming and gunshots, Billy Aldridge, the police chief, told reporters. Police arrived in less than two minutes, Aldridge said, and could be seen on video running toward the facility. They took Sayer into custody roughly four minutes after the first call came in.

Law enforcement identified the victims as 74-year-old Robert Johnson of Orland, California, and Hull of Chico. The girl Hull was protecting, who Wollam said is just seven, was injured and later released from the hospital.

The violence sent shockwaves through the community, particularly as it emerged that Sayer allegedly sought to perpetrate a shooting like the 1999 Columbine high school massacre, in which two students killed 13 people. He reportedly wore a T-shirt with the words “natural selection” in what officials said was an homage to one of the perpetrators of the Columbine massacre.

“It’s shattering. Tragic. It’s something you hope will never happen,” said Wheeler. “We work so hard to make it safe and welcoming every day.”

Chico has been shaped by tragedy in recent years. The city has repeatedly welcomed fire victims and thousands of firefighters responding to the major blazes that have affected the region. The population grew significantly after the 2018 Camp fire, which destroyed the town of Paradise and killed 85 people.

But this was a very different type of loss. The grief is palpable.

On Tuesday evening, residents gathered for vigils at a local church and outside the library. The city is still in shock right now, said Richard Yale, the former rector of St John the Baptist church, who spoke at the vigil there.

“In a community this size, we’re only a few degrees away from someone personally connected,” Yale said.

Aside from flowers laid over the sign, at a distance the library looks almost the same as it did before. It is only up close that there are traces of what occurred inside – a board covering a shattered window, a rug folded over on itself in a hallway and an abandoned book bag next to the door.

A few hundred people stood under the tall trees outside the library where a local pastor sang and sought to comfort the community.

“The truth is this there are no words I can say today or that any of us can come up with that make sense of how we feel,” Rev Robert Morton told the crowd.

Wollam attended the vigil outside the library on Tuesday evening and shared memories of his friend with the Guardian.

“Hero is the word that comes to mind. He took Juniper, the little girl, into his life. [She] wasn’t his daughter, but he treated her like I treat my daughter. And he ultimately gave his life protecting her,” he said.

The city mourns too for the family of the alleged shooter, he added.

“As difficult as it is [with] the young man, the prayers are with his family because they’re going through all of it right now too. They’re not responsible for his actions.”

Wheeler, the branch manager, was moved to tears during Tuesday night’s vigil and said she has been heartened by the show of support from residents. Her staff is hurting but resilient, she said.

“There’s a foundation of strength. Whether it’s Covid, whether it’s one of the many fires, I know that they have tremendous strength,” she said.

After the vigil, people walked together around the library in what they described as an effort to reclaim the space from the horrors that unfolded inside.

No one was sure exactly who organized the vigil at the library, city councillor Addison Winslow said, but people came nonetheless. The history of tragedy here means people show up for each other, he added.

But the incident was reminder that the community is not immune to the type of gun violence that has occurred at schools, workplaces and malls across the country.

“This time it was just here in our library,” he said.