UPDATE: As of 5:37 p.m. Tuesday, police have confirmed seven people are injured. Douglas County Undersheriff Holly Nicholson-Kluth said there's no word on whether there are any fatalities in the shooting. There are two suspects in custody.
ORIGINAL TEXT:
(Highlands Ranch, CO) -- There is a massive police response for a school shooting south of Denver.
The Douglas County Sheriff's office says at least two people were injured at STEM School Highlands Ranch. Other reports say one person is in custody and police were looking for two other suspects. A third suspect is being "engaged" by police. The sheriff's office tweeted it was an "unstable situation."
Officers are going classroom to classroom trying to clear the school.
The STEM charter school is on lockdown and every other school in Douglas County is on lockout.
This is a developing story. Check back for updates.