In what has become a grim ritual, districts across the Denver area moved Wednesday to reassure families that their children are safe in the wake of yet another school shooting.

District leaders emailed families, deployed extra security and counselors, and shared resources to help children handle trauma in response to Tuesday’s shooting at STEM School Highlands Ranch in Douglas County. The shooting left one student dead and eight injured; two students have been arrested.

“Our crisis team is prepared to be out in schools today, and I want to reiterate that the safety and mental health of our students is always our number one priority,” Denver schools chief Susana Cordova wrote in an email to families.

The Denver district also responded to safety concerns by closing at least one school’s campus Wednesday. The district announced that South High School had been placed on lockout, meaning that no one could enter the campus because of a perceived threat from outside the school.

The Denver police department tweeted that officers had investigated a tip received through Safe2Tell, Colorado’s school safety reporting system. Two hours later, the department tweeted an update, saying that investigators “do not believe there is a credible threat at South” but that the district had kept the school on lockout “in an effort to remain cautious.”

The STEM School shooting comes just three weeks after schools across the region were closed after authorities warned of a potential threat posed by a woman “infatuated” with the Columbine school shooting who had traveled to Colorado and purchased a gun. After a one-day closure, officials discovered that she had killed herself.

That episode — along with last month’s 20th anniversary of the Columbine shooting and shootings in schools and other public places across the country — placed local students in a constant state of stress that educators are struggling to manage, a Denver teacher wrote in a piece for Chalkbeat in April.

“Teacher prep classes don’t teach you how to talk about gun violence this country,” wrote the teacher, Stacey Hervey. “And while students in high school put on a brave face, you can see the fear and worry in their eyes.”

District leaders nodded to that dynamic after the STEM School shooting as they distributed resources for talking to children about violence. “We know too well that the pain of these incidents spreads to children who witness the shootings, friends of the victims and kids who now live in fear,” Cordova wrote.

Katy Anthes, Colorado’s commissioner of education, said during the State Board of Education meeting Wednesday that she was thankful that educators have adapted to new and emotionally wrenching demands of their jobs.

“They never asked to be experts in crisis response in this way,” she said. “This is complex enough.”

Anthes said school districts are getting better at responding to tragedies, for instance by sharing buses, mental health professionals, and security personnel with each other and by getting resources to parents. She praised state lawmakers for trying to make more mental health resources available for students but said students still need more.

The Mental Health Center of Denver circulated its “Coping with Tragedy” tips, tweeting, “We are so sad to yet again share resources in the wake of a school shooting, this one so close to home.”

Messages distributed by the Mapleton, Adams 14, Aurora, and Jefferson County districts also contained tips for counseling children distressed by the latest shooting. Several emphasized that existing safety procedures are already keeping students safe.

“I know media stories about school violence make it seem like sending our children to school is a risky proposition,” Jefferson County schools chief Jason Glass wrote to families. “However, our schools are one of the safest places our children can be.” (That’s true.)

On Twitter, Glass broadened his critique, faulting lawmakers’ response to a seemingly relentless drumbeat of mass shootings.

“As the political solutions become bogged down along the same partisan lines and arguments, tomorrow, the people in and around schools will be taking the steps to keep our schools safe,” Glass tweeted on Tuesday evening. “Everyone. Can. Do. Something.”

Glass reiterated those points during a district school board meeting Wednesday morning.

“There have been a number of expressions of grief and connectedness and love and thoughts and prayers and I know that people are getting frustrated with those statements or sentiments,” he said.

He added, “I know that we are all frustrated with the lack of any significant progress on this at any political level but the people that are working in the schools are working on this and we have been working on it and we will continue to work on it.”

A vigil will be held in Highlands Ranch on Wednesday evening by the  Colorado chapter of March for Our Lives. The national student-led movement to curb gun violence began after 2018’s shooting at Florida’s Parkland High School that killed 17 students and teachers.

Gov. Jared Polis ordered flags across the state to half-staff for the next week to honor victims of the STEM School shooting.