They, like so many others, thought they had taken the steps to avoid this.
The school district had an active-shooter plan, and two armed police officers walked the halls of the high school. School district leaders had even agreed last autumn to eventually arm teachers and staff under the state's school marshal programme, one of the country's most aggressive and controversial policies intended to get more guns into classrooms.
They thought they were a hardened target, part of what's expected today of the American public high school in an age when school shootings occur with alarming frequency. And so a death toll of 10 was a tragic sign of failure and needing to do more, but also a sign, to some, that it could have been much worse.
"My first indication is that our policies and procedures worked," J.R. "Rusty" Norman, president of the school district's board of trustees, said on Saturday (US time), standing exhausted at his front door. "Having said that, the way things are, if someone wants to get into a school to create havoc, they can do it."
The mass shooting — which killed 10 people and wounded 10 others in this rural community outside Houston — again highlighted the despairing challenge at the centre of the ongoing debate over how to make the nation's schools safer. It also hints at a growing feeling of inevitability, a normalisation of what should be impossible tragedies.
The gunman in Santa Fe used a pistol and a shotgun, firearms common to many South Texas homes, firearms he took from his father, police said. So there were no echoes of the calls to ban assault rifles or raise the minimum age for gun purchases that came after the shooting three months ago in Parkland, Fla.
Most residents here didn't blame any gun for the tragedy down the street. Many of them pointed to a lack of religion in schools.
"It's not the guns. It's the people. It's a heart problem," said Sarah Tassin, 61. "We need to bring God back into the schools."
Texas politicians are pushing to focus on school security — the hardening of targets.
Gov. Greg Abbott (R) said he planned to hold roundtable discussions starting Tuesday on how to make schools even more secure. One idea he and other state officials mentioned was limiting the number of entrances to the facilities. Rep. Randy Weber (R-Tex.) said Congress eventually would consider legislation focused on "hardening targets and adding more school metal detectors and school police officers."
But the horror in Santa Fe shows that there are limits there, too.
Norman said he saw school security as a way to control, not prevent, school violence. And the school district had some practice. In February, two weeks after the Parkland shooting, Santa Fe High went into lockdown after a false alarm of an active-shooter situation, resulting in a huge emergency response. The school won a statewide award for its safety programme.
"We can never be over-prepared," Norman said. "But we were prepared."
His school board approved a plan in November to allow some school staff members to carry guns, joining more than 170 school districts in Texas that have made similar plans. But Santa Fe was still working on it, Norman said. People needed to be trained. Details needed to be worked out, such as a requirement that school guns fire only frangible bullets, which break into small pieces and are unlikely to pass through victims, as a way to limit the danger to innocent students.
All of these efforts, Norman said, are "only a way to mitigate what is happening."
The search for red flags about the alleged gunman's intentions continued Saturday — another familiar hallmark of school shootings.
Dimitrios Pagourtzis, the 17-year-old student who police said confessed to the shooting, was being held without bond at a jail in Galveston. Wearing a trench coat, he allegedly opened fire in an art class, moving through the room shooting at teachers and students, and talking to himself. He approached a supply closet where students were barricaded inside, and he shot through the windows saying "surprise," said Isabelle Laymance, 15.
The gunman shot a school police officer who approached him, then talked with other officers, offering to surrender. The entire episode lasted a terrifying 30 minutes, according to witnesses and court records.
The Pagourtzis family released a statement on Saturday saying they are "shocked and confused" by what happened and that the incident "seems incompatible with the boy we love".
Nicholas Poehl, the Galveston attorney for Pagourtzis, said his client appeared "pretty dazed" when he met with him Saturday and that it would take time for him to learn what happened.
The alleged gunman's classmates and parents said they saw no signs of trouble before the shooting, though some said he had seemed somewhat depressed in recent months.
Bertha Bland, whose grandson is good friends with Pagourtzis, said she knew the teenager well and described him as "an outstanding kid" and a good student.
Scott Pearson, whose son played football with Pagourtzis, described him as a quiet, normal kid. He didn't talk to him much when he took him home from football practices, but he never got the impression that he was dangerous. He noticed that Pagourtzis regularly wore a trench coat but didn't think much of it.
"Kids do weird stuff," Pearson said. "I don't understand when my son wears a hoodie out in 90-degree heat, either."
Pagourtzis improved as a football player between sophomore and junior years, moving from second to first string as a defensive tackle on the junior varsity squad, according to Rey Montemayor, an 18-year old senior quarterback.
Pagourtzis spent a lot of time in the weight room.
Eventually Pagourtzis, who wore number 69, was doing reps of 185 pounds on the bench press. "He worked hard," Montemayor said. "Even got stronger than me."
On the team, Pagourtzis was well liked and respected, even though he mostly kept to himself, ear buds in his ears in the hallways and in the locker room. He was "very normal, cool," Montemayor said. "He would joke around but was also quiet — not an open book."
Local and federal officials revealed little new information about the shooting or the investigation on Saturday. So far, investigators have not found any link to terrorism or political extremism in the suspect's background that would offer a motive for the attack, according to a person close to the investigation.
The evidence recovered in the first day of the probe suggests that the suspect was a disturbed young man without any particular ideology, though it is still early in the investigation and new facts could emerge, the person said.
Authorities here said police reacted as they should have to the shooting incident, praising the initial response, which included two school police officers trying to intervene, though they have not yet provided details of the interaction that led to the teen's surrender.
Galveston County Judge Mark Henry described the quick actions of the school police officers as "very critical."
Santa Fe Independent School District Police Chief Walter Braun said at a news conference that the police officer wounded in the shooting was in "critical but stable condition" at a hospital. He said his officers "did what they were trained for. They went in immediately."
Some students, escorted by police, were briefly allowed back on the school campus to retrieve backpacks and their vehicles. But the high school remained cordoned off as a crime scene.
The town did not come to a standstill as it dealt with the aftermath of the shooting: People still ran errands and had yard sales and barbecues. The community library closed "out of respect for the victims," but organisers of a library benefit sale decided to hold their event as planned in the lobby and parking lot. The Santa Fe High baseball team was still scheduled for a playoff game Saturday night.after cancelling one on the day of the shooting.
The shooting didn't seem to rattle beliefs or prompt the calls for change that followed the Parkland shooting. Norman Franzke, 69, whose granddaughter safely escaped Santa Fe High, noted that guns have been part of the culture here for generations. When he attended, students kept shotguns on racks in their pickups, ready for hunting after school.
"I don't think this will change the mentality of this community," Franzke said. "There may be some changes in how kids enter and leave school. But even then, he was a student, so he would still have had access."
At Red Cap restaurant, a popular diner down the road from the high school, the sign outside no longer advertised fried green tomatoes and Boudin balls. It had been changed to read "Prayers for Santa Fe."
Inside, Tassin, who works at Red Cap, teared up as she thought about all the teens and their parents who stop in there. She considers them family. But she didn't blame guns for Friday's shooting. She didn't blame mental health. She didn't know where to lay blame. There had been so many school shootings. And now, at Santa Fe High.
Something was going on, she said. But she didn't know what.