A 16-year-old Colorado student at Evergreen High School in Jefferson County opened fire Wednesday, injuring two fellow students, before taking his own life.

One of the injured remains in critical condition, according to The Denver Post, with hundreds of law enforcement officers arriving at the scene, at around 12:24 p.m.

The other injured student is currently in stable condition.

The shooting unfolded both inside and outside the school, with law enforcement responding quickly. A fourth student was injured while fleeing the scene.

Police have not yet released the shooter’s name, but Denver’s ABC 7 reports that police were seen searching his residence, near Corwina Park, on Wednesday evening.

“Obviously, we’re going to focus on that suspect’s home, his car, his locker, all the things that we need to do to find out more about him and maybe why this happened,” Jefferson County Sheriff’s Office Spokeswoman Jacki Kelley said.

So far, it’s unclear what was found inside the shooter’s home.

As CrimeOnline previously reported, a mother said her freshman son told her he was near a door in the lunchroom when the shooting started and heard 15 to 30 gunshots.

“I know they’ve done drills at school in classrooms, but they were at lunch,” she said. “So that’s what, something that many students have said is that they just didn’t even know what to do, like a lockdown drill, with this happening at lunch.”

According to FOX 31, the last shooting is one of 13 school shootings that have taken place in Colorado in an over 50-year time span.

Check back for updates.