Witness to Evergreen school shooting in Colorado says he saw shooter holding student "by the neck"

As families, students, and the Evergreen community grapple with emotions and questions in the days since the shooting at Evergreen High School, Delmer Martinez is grappling with what he witnessed and caught on camera as the tragedy unfolded before him.

"In that moment, I didn't know how to react," said Delmer Martinez. "I got out of the car and started to film."

Martinez tells CBS Colorado, he and another coworker were working a roofing job in Evergreen Wednesday and had just finished up their lunch break, when they started to drive down Buffalo Park Road near Olive Road. That is when a police officer sped past them and got out of their car.

"It was there where we saw a young person fighting," he tells CBS Colorado in Spanish. "He came out holding another student by the neck and the police were saying something, for him to stop. So, the student shot at the other teen and threw him. He threw him to the ground."

After that is when Martinez started recording. He was stopped on the side of the road and unable to drive out of the area as more police cars started to arrive. 

"The police didn't know how to react, whether to attend to the teen on the ground or follow the other one," said Martinez.

Videos shared by Martinez show what happened after he says the teen suspect shot the other student. Other officers quickly arrived on scene as one of them followed the suspect up a dirt driveway.

"He went off walking about 10 meters," said Martinez.

Officers appear to tell the suspect to put his weapon down. That's when Martinez says he heard a gunshot.

"Everything lasted about 10 minutes," he said.

Martinez's video shows an officer performing first aid.

"We wanted to leave but there wasn't anywhere we could go," said Martinez.

Martinez says they didn't have cell reception at that location and didn't know what was happening to the students.

"We didn't realize until 5:30 p.m. that we were filming something that was a lot more serious," he said. 

In hindsight, he wishes he could've done more to help in that moment.

"I was scared, it didn't cross my mind to help," said Martinez.

However, he hopes this video can paint a better picture of what happened outside of the school, and the quick response from police on the ground.

Two students who were shot at the high school remain in Denver-area hospitals. One is still in critical condition and the other was upgraded to serious condition on Friday. The shooter died from a self-inflicted gunshot wound, according to the Jefferson County Sheriff's Office.