Published 11:08 a.m. | Updated 6:24 p.m.
Douglas County Coroner Jill Romann identified the student killed in the shooting at STEM School Highlands Ranch as Kendrick Ray Castillo.
He was 18 and days away from high school graduation.
On social media, Castillo is seen in photos competing in robotics competitions and spending time with friends and family in the mountains with a Jeep. He was fascinated by engineering and eager to help others, his boss Rachel Short said.
Short is the chief executive officer of Baccara USA, the manufacturing business where Castillo worked part-time for the past 18 months. He had initially interned at the company, and did "such an outstanding job," Short offered him a position.
"Engineering and technology is what drove Kendrick," Short said. "For a very young 18-year-old to bring the value and the insight and the general knowledge that he did, it’s something that I’ve never seen in my career, especially somebody at this age."
Short said she'll miss Castillo's smile, and described him as "upbeat caring, loving, and truly compassionate."
His father, John Castillo, told The Denver Post Wednesday morning that, “He was the best kid in the world.”
Castillo reportedly jumped at one of the shooters.
“That’s when Kendrick lunged at him and he shot Kendrick, giving all of us enough time to get underneath our desks, to get ourselves safe and to run out of, across the room to escape,” Nui Giasolli told the Today Show Tuesday night.
The news didn't surprise Short at all.
"I would have no doubt that would have been his absolute first reaction, without hesitation," she said.
Eighteen-year-old Brendan Bialy said he, Castillo and a third student tried to stop the gunman by charging at him. Bialy, a student Marine recruit, said the attacker got some shots off, fatally wounding Castillo. But Bialy said he was able to wrestle the attacker's firearm from him.
Meanwhile, the family of another student who said he was involved in the disarming of the gunman released a statement saying he was shot twice while disarming one of the attackers. Joshua Jones' family called Castillo "a special hero" and said, "we consider ourselves fortunate the result was not much, much worse."
The family declined to comment further.
Short said she is comforting not only herself, but also everyone in the company that knew Castillo.
"Me personally, I’m broken and devastated, and in my role I have responsibilities for an entire organization that is broken and devastated and just at a lost for words for the situation," Short said. "I can honestly say nothing in life prepares you to go through something like this."
The business has already decided to honor Castillo in a number of ways.
In the lobby, there will soon hang a photo of Castillo with his coworkers, bordered by handwritten memories shared by the team.
And behind the scenes, Short said they plan to some of their signature assembly techniques and proccsses after him, too.
"The number one memory is his smiling face that was present every day, every moment that he was at work with us," Short said.
CPR News reporters Hayley Sanchez and Michelle Fulcher, as well as The Associated Press, contributed to this report
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