He says the guard drew his weapon and apprehended the person.
John Castillo, Kendrick's father, described him as "the best kid in the world", in an interview with the Denver Post.
A member of the school's robotics club and a relentless tinkerer, Castillo had an infectious smile and gentle sense of humor, according to friends.
There were around 1,800 students on campus at the time of the attack, Sheriff Spurlock said. The company's CEO said "Castillo loved engineering and was eager to help people".
"I was blessed by something", he said.
A shaken Michael Malone pleaded for something to change after a school shooting that left one student dead took place at a Highlands Ranch public charter school in his suburban Denver community.
The White House said the president's daughter and adviser did not want to divert resources or attention from the shooting.
Though authorities initially said they were looking for a possible third suspect, Nicholson-Kluth said they are no longer looking for another suspect.
"What I saw yesterday was the absolute best of people", he added. "We did struggle with the suspects to take them into custody".
The state had just commemorated the 20th anniversary of the notorious Columbine school shooting in which two heavily armed students aged 17 and 18 killed 12 of their classmates and a teacher on April 20, 1999, before committing suicide.
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It was Biden's first trip to SC , a critical early primary state where winning the African American vote is crucial. So the more money that we invest in the State Department, it doesn't just save ammunition.
He said it was not surprising to him that Kendrick was said to have charged one of the shooters as they entered a classroom.
"Who we are is a kind, compassionate, caring people, and this does not define us".
"I can tell you that there were shots fired", Spurlock continued.
"This is not who we are", said Brauchler, who was also the prosecutor in the 2012 movie theater shootings in Aurora, Colo. "The next thing I know he's pulling a gun and he's telling nobody to move".
Image copyright Facebook, courtesy of Devon Erickson Image caption Devon Erickson, 18, has been named as one of the suspects How did the Colorado shooting unfold?
One victim, an 18-year-old male, later died of his injuries, Mr Spurlock said a short time later.
It was not immediately clear when the younger suspect, who has not been identified, would appear in court.
Highlands Ranch is a suburb of Denver, and the school is roughly 14 miles from the city center.
No school resource officer was assigned to the school, but the school has its own private security and other officers in the area were able to respond to the scene.
On May 7, officials identified the juvenile suspect, who has not been named, believing she was a boy at first. Here's what we know so far.
Spurlock declined comment when asked by reporters if the juvenile suspect is transgender.