Jesse Sarles manages the web content and website operations for CBS Colorado. He writes articles about Colorado news and sports in and around the Denver area.

The shooter at Evergreen High School last week fired 20 rounds within 9 minutes. That's according to a new preliminary report from the Jefferson County Sheriff's Office about the shooting in the Colorado foothills on Wednesday.

In the early afternoon, calls to 911 about the shooting started coming in, and within moments -- at 12:24 p.m. -- the first deputy was dispatched to the school. Investigators say the shooter fired several rounds inside the school and one student was injured during that time. A spokesperson for the sheriff's office previously said that the shooter used a handgun.

The teenage shooter then left the building, crossed the school's football field and then shot a second student at the intersection of Olive Road and Buffalo Park Road.

Jeffco deputies responded within 2-and-a-half minutes to the scene and confronted the shooter.

The sheriff's office praised the quick thinking of teachers, students and staff when the shots rang out.

"While deputies responded quickly, the actions taken by teachers, staff, and students inside the school undoubtedly saved lives. They relied on the safety protocols and lockdown procedures they have practiced, and those immediate actions made a critical difference," the sheriff's office wrote in a news release.

The shooter was identified as 16-year-old Desmond Holly, and he died from a self-inflicted gunshot wound that was when the confrontation with law enforcement took place. Holly was a student at the school.

One students who was shot remains in the hospital with critical injuries. The other student victim's condition was upgraded from critical condition, but that student remains at the hospital. One of the injured students is Matthew Silverstone, an 18 year old.

Classes at Evergreen High School are canceled all week, and mental health resources are available for students and others in the community who are struggling in the wake of the shooting.

Shooter fired 20 rounds at Evergreen High School within 9 minutes, Colorado sheriff's office says