Colorado teen called mum while subduing school shooter

A student who helped thwart a shooting at a suburban Denver high school says he was still pinning one of the attackers down when he decided to call his mother.

Joshua Jones, an 18-year-old senior at STEM School Highlands Ranch, said during a news conference he was watching "The Princess Bride" in his British literature class when a classmate pulled a gun and told everyone to stay still.

Jones said he was acting on instinct when he, Kendrick Castillo and Brendan Bialy subdued one of two students who attacked the school south of Denver on May 7.

Castillo was killed, and Jones was shot twice in one leg but said he is recovering quickly.

"There wasn't a whole lot that was going through my mind at the time. Adrenaline and tunnel vision are a crazy thing," said Jones, who described himself as just a normal teenage kid.

"They make it so that you don't really focus on anything but what's right in front of your face at that moment."

He did, however, have the presence of mind to call his mum.

"She always has been a problem solver for me," he said, adding that she told him not to worry.

"It was a pretty quick conversation.

"It was really just something like, 'Hey, Mum. There's been a school shooting. I've been involved. The authorities are on the way. They're going to get an ambulance and I'm going to go to the hospital. That's all I got right now for you.'"

The second shooter was captured by an armed security guard.

Authorities have said these acts of bravery helped minimise the bloodshed from the attack, which also wounded eight students, all of whom have since been released from the hospital.

"We're going to hear about very heroic things that have taken place at the school," Douglas County Sheriff Tony Spurlock said shortly after the shooting.

Devon Erickson, 18, and 16-year-old Alec McKinney, who is listed in court records as Maya, are accused of walking into the school through an entrance without metal detectors and opening fire in two classrooms.

Investigators have not offered a motive and declined to say how the students got the handguns that were used in the attack.

The two are being held on suspicion of murder and attempted murder, and prosecutors are expected to reveal Wednesday if they are going to charge McKinney as an adult.

Colorado law allows prosecutors to file adult charges of serious felonies against 16- and 17-year-olds without prior approval from a judge.

Jones declined to talk about the shooters Tuesday, instead focusing on Castillo and his own physical and emotional recovery.

He said he is "still in a bit of a funk" emotionally ... "but physically, I'm recovering incredibly well. I'm healing fast. I mean, I'm a young kid."

The shooting happened nearly three weeks after the neighbouring town of Littleton marked the 20th anniversary of the Columbine High School attack that killed 13 people.

The two schools are separated by about 11 kilometres south of Denver.