HIGHLANDS RANCH, Colo. >> The three students who disarmed a gunman in a Colorado school shooting leapt up from their desks without a word and with no thought for their own safety when they spotted the gun, recounted one of the young men.

They slammed the teenager, a classmate of theirs, against the wall and struggled with him when shots rang out. Kendrick Castillo, who led the charge, slumped to the ground.

His close friend, Brendan Bialy, wrestled the gun away and called out to Castillo. There was no response, Bialy told a roomful of reporters on Wednesday as he recalled what happened the previous day at STEM School Highlands Ranch.

“Kendrick went out as a hero,” Bialy said. “He was a foot away from the shooter and instead of running the opposite direction he ran toward it.”

Authorities said the actions of Castillo, Bialy and Joshua Jones minimized the bloodshed from Tuesday’s attack at the school south of Denver that wounded eight students along with killing the 18-year-old Castillo. The injured includes Jones, who was shot twice, according to a statement released by his family.

A private security guard employed by the school detained the second armed suspect, officials said. The guard fired his gun during the confrontation, according to a law enforcement official who spoke on condition of anonymity because the official was not authorized to release the information.

The official did not say whether anyone was injured by the guard’s weapon. News organizations have reported that authorities are investigating whether the guard fired at a responding sheriff’s deputy and wounded a student.

The security guard’s attorney, Robert Burk, did not confirm or deny the reports, but he said his client acted in the best interests of protecting the children at the school. He did not name the security guard.

“He ran there as quick as he could and took what I think is decisive action that helped save lives,” Burk said today.

The guard was employed by Boss High Level Protection, a company started by a former SWAT team leader who responded to the Columbine shooting. The owner, Grant Whitus, told The Associated Press the security guard is a former Marine who ran to the area of the shootings and confronted one of the armed students in a hallway.

The guard drew his weapon and apprehended the person, Whitus said.

“He doesn’t even realize how many lives he saved by stopping a school shooting,” Whitus said.

Douglas County School District spokeswoman Paula Hans declined to comment on any actions the guard took and referred questions to the sheriff’s department. STEM School administrators didn’t immediately respond to an email from The Associated Press.

Castillo was remembered Wednesday night at a vigil that was hit by disruptions, with many students staging a walkout amid complaints the vigil had been politicized and failed to include their voices.

Hundreds packed a high school gym for the event organized by the student arm of the Brady gun control group that included pro-gun control speeches by presidential hopeful Sen. Michael Bennet and U.S. Rep. Jason Crow, both Democrats.

At one point, someone shouted that students should be allowed to speak, and organizers talked with students in a hallway about how to include them.

Some students chanted and others railed against the media and called for remembering Castillo. Students eventually were invited to speak. Teacher Emily Muellenberg told Colorado Public Radio that organizers had reached out to students before the event but didn’t hear back.

During the interview about the shooting ordeal, Bialy acknowledged that he was scared, but he said the shooters “completely and utterly lost to good people.”

The attackers were identified by law enforcement officials as 18-year-old Devon Erickson and a 16-year-old who prosecutors identified as Maya McKinney but whose attorney said uses male pronouns and the name Alec. The two allegedly walked into the STEM School Highlands Ranch through an entrance without metal detectors and opened fire in two classrooms.

Because the attack happened only miles from Columbine High School and just weeks after the shooting’s 20th anniversary, questions quickly arose about whether it was inspired by the 1999 massacre. But investigators offered no immediate motive.

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. He worked part-time at a local manufacturing company that had offered him a job after an internship because he was such a standout employee.

“To find he went down as a hero, I’m not surprised. That’s exactly who Kendrick was,” said Rachel Short, president of the company, Baccara.

Cecilia Bedard, 19, had known Castillo since elementary school and said he was always friendly, modest and excited to help people. He made a point of always joining his father at Knights of Columbus fundraisers and bingo nights.

“He was amazing,” Bedard said. “He was honestly the sweetest kid I ever met. Never said a mean joke.”

Both suspects were students at the school, and they were not previously known to authorities, Spurlock said.

Erickson made his first court appearance Wednesday and kept his head down. His black hair, streaked with purple dye, covered his face as he nodded in response to most of District Court Judge Theresa Slade’s questions. At one point, the judge requested a verbal answer to whether he had any questions about the proceedings. Erickson simply replied “No.”

McKinney, who has a short brown haircut, made eye contact with the judge and answered questions in a clear but quiet voice, saying “Yes, your honor” and “No, your honor.”

District attorney George Brauchler said he has not decided whether to file adult charges but added that McKinney is old enough to be charged as an adult without a judge’s review.

Formal charges were expected to be filed by Friday. Brauchler said he could not discuss any motive or weapons used in the attack.

Brauchler said the community remains resilient in the face of multiple shootings, including the 1999 Columbine school massacre, the 2012 theater shooting in the Denver suburb of Aurora and the 2013 shooting at Arapahoe High School.

The attacks are “aberrant acts” although they might seem otherwise to the rest of the world, he said. “Who we are is a kind, compassionate, caring people, and this does not define us.”