The father of a student killed in a Colorado high school shooting on Tuesday said his son was a hero and he wanted people to know about him.
Kendrick Castillo, 18, died in the shooting, according to authorities.
Student Nui Giasolli told NBC's "Today" show that she was in her British Literature class when one of the suspects, identified by sheriff's officials as 18-year-old Devon Erickson, came in late and pulled out a gun.
Giasolli said Castillo lunged at the gunman, who shot the teen.
Castillo's actions gave the rest of the class time to get underneath their desks and then run across the room to escape to safety, Giasolli said.
As gunfire echoed through the school, students hid or ran through the halls, some shouting.
"I want people to know about him," the teen's father, John Castillo, told KMHG through tears.
The chief executive officer of the manufacturing business where Castillo worked part-time for the past 18 months told the Associated Press that he was fascinated by engineering and eager to help others.
Rachel Short of Bacara USA said Castillo started working at her company last year as an intern. She said he was such a terrific employee they offered him a part-time job.
Short said Castillo was funny and empathetic and loved helping people.
"To find he went down as a hero, I'm not surprised, that's exactly who Kendrick was," Short said.
Castillo was a member of the school's robotics club called FRC 4418 Impulse. He was set to graduate on Friday, according to media reports.
"We're heartbroken by the death of Kendrick Castillo, a victim of the STEM School Highlands Ranch shooting" FIRST tweeted, a nonprofit that aims to advance youth STEM education. "Kendrick was a member of @Frc4418, of which his father is Lead Mentor. Our hearts go out to Kendrick's family, friends, & all affected by the shooting."
Castillo's classmate thanked three other students who she said also ran toward the gunman. Giasolli said one of them was Brendan Bialy, a current poolee in the Marine Corps Delayed Entry Program.
"Brendan's courage and commitment to swiftly ending this tragic incident at the risk of his own safety is admirable and inspiring," the Marines said in a statement to FOX 31 Denver. "His decisive actions resulted in the safety and protection of his teachers and fellow classmates."
An armed security guard also confronted and detained one of the shooters. Authorities said these acts of bravery helped minimize the bloodshed from the attack.
"We're going to hear about very heroic things that have taken place at the school," Douglas County Sheriff Tony Spurlock said Wednesday.
Douglas County sheriff's officials said Erickson and a younger student who is a juvenile and was not identified walked into the STEM School Highlands Ranch through an entrance without metal detectors and opened fire on students in two classrooms at around 1:50 p.m. local time.
Both were taken into custody, authorities said.
Both suspects were students at the school and they were not previously known to authorities, Spurlock said.
Eight other students were injured in the attack at the public charter school, which has a focus on science, technology, engineering and math. It has more than 1,850 students enrolled in kindergarten through 12th grade.
The shooting took place exactly a week after a gunman killed two students and wounded four at the University of North Carolina-Charlotte. It also comes nearly three weeks after neighboring Littleton marked the grim 20th anniversary of the Columbine school massacre that killed 13 people.
The two schools are separated by about 7 miles in adjacent communities south of Denver.
This story was reported from Los Angeles. The Associated Press contributed.