Jeffco Public Schools’ security chief was already losing sleep over the Columbine anniversary. And then this week happened.

John McDonald already struggles with sleepless nights. The man in charge of the safety and security of the 86,000 students attending Jeffco Public Schools often wakes from the recurring nightmare that visits him late, the one where the kindergartners are running to him in search of protection.

As the 20th anniversary of the Columbine High School mass shooting approached, the call came in, ramping up his anxiety even further. An agent with a local terrorism task force called McDonald’s cell phone Tuesday morning, slightly before lunch, to let him know there was a credible threat. Sol Pais, an 18-year-old woman from Surfside, Florida, obsessed with the Columbine massacre, had taken a flight to Colorado and was in contact with local gun stores, the agent told him.

That phone call triggered a series of steps that ultimately would result in the shuttering of schools throughout the Front Range. Superintendents held phone calls late into the night before deciding more than half a million students should stay home. It wasn’t until Pais’ body was found near a remote trail at the base of Mount Evans Wednesday morning that teachers, parents, students and officials like McDonald could finally relax. Authorities said she killed herself.

“The story of Columbine still looms pretty large in Jefferson County as it does across this state and in the rest of the country,” McDonald, Jeffco schools’ executive director of school safety and security, said during a news conference Wednesday where he and other officials announced the threat posed by Pais had passed.

For McDonald, the phone call about Pais alerted to him an immediate threat, one that had to be taken seriously and warranted an aggressive response.

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Columbine groupies show up every year, especially near April 20

He is used to Columbine groupies. They pour in from all parts of the country, especially when the anniversary of the Columbine tragedy draws near. He grows so jumpy when the week of April 20 arrives that he ends up staying most nights at the school, working.

Over the past two weeks, authorities registered more than 150 reports of people attempting to make a pilgrimage to Columbine, McDonald said during an interview.

He said authorities recently arrested one man who came from Texas and drove a car backwards into the school parking lot. When confronted, the man told officers the soul of one of the Columbine killers had invaded his body. Police found a knife in the car. In the jail, he smeared feces on his cell walls.

McDonald considered the warning about Pais perhaps the most serious of the Columbine obsessives in recent memory.

“This one felt different,” McDonald recalled. “It was different. It certainly had our attention.”

He called a school resource officer at Columbine to launch well-practiced protocols as officials began assessing how to respond to the threat. Extra security swung into place. Within hours, law enforcement officials confirmed that Pais had bought a pump-action shotgun and ammunition at a local gun store.

Frank DeAngelis, who was principal during the Columbine mass shootings and has since retired, happened to have stopped by the school on Tuesday. He immediately began reaching out to the 15 or so staff members he knew had been there that terrible day 20 years ago, seeking to comfort them.

“The month of April, it does something to us all,” DeAngelis said later, during Wednesday’s news conference.

Back before the Columbine attack, students practiced fire drills, but not active shooter drills or lockdowns or lockouts, he recalled. Now authorities have procedures and plans in place, DeAngelis said. Police agencies and school officials share information. Students know what to do if a school shooter invades.

“The support system is there now,” said DeAngelis, who has recounted in other press reports that every morning before he gets out of bed he recites the names of the Columbine victims in tribute.

Schools made the tough call to shut down Tuesday

McDonald said officials had to make a tough call this week. They could draw on sufficient fire power and a strong enough police presence to allow students to go to school at Columbine on Wednesday.

But what if Pais showed up, forcing a shootout in broad daylight on school grounds that would traumatize students for the rest of their lives?

As discussions continued through the day and into the night among metro-area superintendents, “there was a consensus that any of our schools could be targeted,” said Jason Glass, the superintendent for Jeffco Public Schools. Eventually the call was made to close metro-area schools, he said.

McDonald was relieved. As night arrived, a new threat emerged. He had to deal with 12 reports to Safe2Tell, the platform for anonymous tips on potentially harmful school behavior. Students at a different Jeffco school were warning that their school had been targeted for violence by another student. McDonald spent his night dealing with that situation, eventually resolving it, while also dealing with Pais.

In the end, McDonald got fewer than three hours of sleep, reminiscent, he would later say, of his days in the Army. For him, it’s just part of the job. He doesn’t like to take vacations. He worries. What will happen if he is gone? Who will be there to ensure protection?

For McDonald, it’s personal. In 1989, McDonald’s older sister Christy was assaulted, strangled and stabbed to death by a stranger who broke into her condo. He suspects that someone who has been touched by violence, as he has, always wants to do what they can to stop the next attack.

By Wednesday, with the news that Pais was dead, authorities were moving toward reopening schools on Thursday, with increased security precautions in place.

McDonald, who said he plans to stay overnight at Columbine for the rest of the week, was still anxious about the planned commemorative ceremonies planned for over the weekend.

“There won’t be much sleep,” he said. “I’ll be working the graveyard shift.”

MORE: Florida woman found dead after manhunt, statewide school closures over threat, “infatuation” with Columbine

But he said he also knew that systems had been put in place to ensure police and school officials would cooperate, that if any new threat developed, there would be an aggressive response. He has seen his security staff grow to 127 people from 10 in 2008, when he took the job as head of security.

“Columbine is not our legacy,” McDonald said. “It is our history. We have learned from our history. A legacy is a continuation of our past.”

“And that is not us.”