Kendrick Castillo's father says son died saving lives during school shooting

It was a split-second decision. Kendrick Castillo didn't hesitate. He hurled himself at the gunman who opened fire Tuesday inside a classroom at STEM School Highlands Ranch at Colorado's Douglas County and died. The 18-year-old robotics aficionado is being heralded for his bravery. 

Kendrick was at his desk ready for his British Literature class. When he saw Devon Erickson, 18, pull out a handgun, he lunged at him. Students and parents believe the shooting's victim count could have been far worse without his courage. 

Douglas County Sheriff Tony Spurlock said there were eight injured: Five had been released by Wednesday morning but three remained hospitalized in intensive care. Castillo told reporters that he is having a hard time accepting his son's decision.

"I want people to know about him," John Castillo told ABC News through tears.

Friday would have been Kendrick's last day at STEM School Highlands Ranch in Colorado. The aspiring engineer was planning to go to Arapahoe Community College in the fall. He also had plans to enjoy his love of mechanics, fishing and hunting this summer.

"It doesn’t surprise me," Kendrick's grieving father said during a Wednesday morning interview with The Denver Post. "He cared enough about people that he would do something like that ... I wish he had gone and hid, but that’s not his character. His character is about protecting people, helping people."

Nui Giasolli said she saw how Kendrick sacrificed his life to save her and the other students. Kendrick was the only one who died at the school Tuesday. Giasolli said she owed him her life. She said his brave act gave them time to escape. 

Kendrick was an award-winning member of the FRC Team 4418 IMPULSE, his school's varsity robotics team. He spent countless hours at the school's engineering labs working with his teammates. They had competed at the Oklahoma Regionals in March. 

On Wednesday, the organizers of the prestigious FIRST Robotics competition released a tribute on Twitter: "We are heartbroken by the death of Kendrick Castillo, a victim of the STEM School Highlands Ranch shooting in Littleton, CO. 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."

Kendrick didn't work alone. The three others who also tackled Erickson survived. Brendan Bial, a member of the Marine Corps Delayed Entry Program, the 8th Marine Corps District, is among them.  Spurlock said there was a second shooter in another classroom. ABC News' Denver affiliate sources said he is a transgender boy. 

Kendrick also had a part-time job at Bacara USA. The owner of the manufacturing company, Rachel Short, described him as a funny and empathetic person who loved others.

"To find he went down as a hero, I’m not surprised," Short told The Associated Press. "That’s exactly who Kendrick was."

Cecilia Bedard, 19, said she had known Kendrick since elementary school.  She described him as friendly and modest. She said he made a point of always joining his father at Knights of Columbus fundraisers and bingo nights.

"He was amazing," Bedard told The Associated Press. "He was honestly the sweetest kid I ever met. Never said a mean joke."

Former Rep. Gabrielle Giffords and activists with Moms Demand Action also issued statements about Kendrick and Riley Howell, a 21-year-old who also died while tackling a shooter at the University of North Carolina at Charlotte last week. 

"The families of Kendrick Castillo and Riley Howell should be planning for their futures, not funerals," wrote Giffords, who survived an assassination attempt in 2011. "This is devastating. Our leaders owe it to them to take action."