DOUGLAS COUNTY, Colorado — Steve Holley's story was one of countless that could be told inside of Northridge Recreation Center in Highlands Ranch Tuesday afternoon. 

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He was one of the hundreds of parents who waited as their children – the youngest are in kindergarten– were bused from STEM School Highlands Ranch to the recreation center a mile and a half away after gunfire rang out in the quiet Denver suburb. 

Holley said this is the third time he’s had to pick up his children due to a lockdown this year. 

“There was a shooting at my son’s school today,” Holley wrote in a heartbreaking Twitter thread that has been widely shared in the aftermath of the event that has once again put Colorado in national headlines. “He’s safe, but … I’m sitting in a gym with hundreds of parents waiting to see their kids.”

It was a sight Colorado has seen before: children being led outside of a school with their hands on their heads to waiting and worried parents, and dozens of news cameras waiting for the latest information from law enforcement, who combed the suburban Denver school from room to room to confirm no one was still in danger.

RELATED: One dead in STEM School Highlands Ranch shooting

One student was killed and eight others were injured when Douglas County Sheriff Tony Spurlock said two of their classmates at the high school went inside and opened fire. Those two suspects are now in custody.

The Douglas County coroner has not released the identity of the student who died, however, the family of Kendrick Castillo, 18, confirmed to NBC News that he was the student killed during the shooting.

There are 1,800 students enrolled at STEM School Highlands Ranch, a K-12 charter academy with an elementary, middle and high school campus.

Holley said children were released from the school by grade. His son was in 6th grade, meaning Holley had to wait behind many other parents. Holley, at least, said he had the benefit of a phone call from his son.

“My son didn’t cry at first,” Holley wrote on Twitter. “He just said there had been a shooting and there was glass everywhere. He started to cry after he said he saw a girl who had been shot being carried out. I asked if he was safe, told him I was on my way, and that I loved him.”

RELATED: One dead in STEM School Highlands Ranch shooting

Holley described the process of receiving reunification forms with police, and sharing in the confusion of other parents as they waited in a gym to see their kids. 

“My wife and I – and most everyone here --- are holding it together,” Holley tweeted. “Once they call 6th grade I’ll probably lose it, then probably, no, I’ll absolutely lose it again when I see my son.”

You can read Holley’s full Twitter thread below. If you can't see it on your device, click or tap here: bit.ly/2VmP6Kj

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