NASHVILLE, Tenn. (WKRN) — Chaos and carnage plagued Texas Tuesday, leaving 19 empty beds where children used to sleep after a teenage gunman opened fire on a fourth-grade classroom. It’s the deadliest shooting at a U.S. school in almost a decade. It has left communities around the country shaken and terrified that something like that could happen in their community.

Inside Tom Joy Head Start Elementary school, staff members are breathing a little easier after the school was placed on lockdown two days in a row after a man made violent threats against students.

It was a call those inside the school never saw coming.

Stephen Robertson (Metro Nashville Police Department)

“We had an unknown caller make repeated calls to our center, claiming to have a desire to hurt children in our centers. He made some descriptions on what he was going to do and what he could do,” said Lisa McCardy, with Metropolitan Action Commission. “Day 2, he did the same thing.”

As soon as the calls came in, the MAC called the Metro Nashville Police Department, who went to work on clearing the entire building. McCardy described how officers checked each classroom before allowing students and parents to leave the building. The threats even delayed graduation ceremonies set to happen, out of precaution.

“We have a shelter-in-place plan, which we, unfortunately, have to have a drill for, and so the children were excellent. They knew where to go and to be quiet and the teachers responded based upon the plan. It’s unfortunate that you have to have plans like that,” McCardy said.

Four days after the first threat, Metro police arrested 30-year-old Stephen Robertson. According to police records, he had called the school directly and told an employee, “The kids are going to blow up in the school.” It was a terrifying moment not only for the students and staff but for the community as well.

Robertson is facing charges including making a threat of mass violence against a school and multiple counts of giving a false report. Records show when responding officers traced the call back to Robertson’s home at a halfway house, he denied any involvement in the crime. The owner of the residence identified the caller’s voice to be Robertsons.

“Everybody, even if you weren’t in the building, your heart was here,” McCardy described.

The terror then heightened, after news of a mass shooting in Texas emerged a week later. The incident reinforced the need to take school threats seriously.

“Then, for yesterday for the Texas Massacre to have occurred that can be very triggering,” McCardy said. “We are now faced with a situation that happened in our country where a threat was taken, and I don’t even know if they knew the threat was coming, and it just happened. So, all of this can be very triggering.”

McCardy told News 2, as details from the mass shooting because clearer, she, like most parents, checked in with her own daughter, who said, “‘I was safe at home and at school’ and when she said that, that hit me because those are supposed to be places of safety for everybody, but in this world, it doesn’t feel like it is.”

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Robertson is being held on a $35,000 bond.