HIGHLANDS RANCH, Colo. – A Colorado teen set to join the U.S. Marines this summer is credited with helping subdue a gunman during a shooting at his Denver-area school on Tuesday.

The Marines said Brendan Bialy helped saved lives during the attack at the STEM School Highlands Ranch. One student died, and two suspects are in custody.

"Brendan’s courage and commitment to swiftly ending this tragic incident at the risk of his own safety is admirable and inspiring," Capt. Michael Maggitti said in a statement. "His decisive actions resulted in the safety and protection of his teachers and fellow classmates."

Bialy joined the Marines under the Delayed Entry Program, and is scheduled to ship out for basic training this summer.

Student Nui Giasolli told NBC's "Today" show that multiple students in her literature class jumped at the shooter, including the student who was fatally shot.

"They were very heroic," she said of the students who confronted the shooter. "I can't thank them enough."

What we know now: Colorado school shooting updates: STEM school to be closed this week after 1 dead, 8 injured

Three of the eight wounded remained hospitalized Wednesday. The family of Kendrick Castillo confirmed to multiple media outlets that the 18-year-old student was killed.

“I want people to know about him,” Castillo's father, John Castillo, told ABC News.

Douglas County Sheriff Tony Spurlock said one suspect is a "female juvenile" after police originally identified the teen as male. The other was identified by police as Devon Erickson, 18.

More: Second suspect in Colorado school shooting is a girl, sheriff says

Spurlock told reporters Wednesday that at least one student encountered a suspect during the shooting but did not say more.

“We’re going to hear about very heroic things that have taken place at the school,” Spurlock said.

Never lie: How to talk to your kids about school shootings, like the one at Colorado's STEM school

Contributing: John Bacon in McLean, Va. Miller also reported from McLean.

This article originally appeared on USA TODAY: Colorado teen who plans to become Marine tackled suspected shooter