The shooting began in the middle school and that many shots were fired, according to the Sheriff's Office.
A third person was "tentatively" a third suspect, Douglas County Undersheriff Holly Nicholson-Kluth said. Officials say some of the wounded students are still at the scene and will be taken to a hospital soon.
At least two people were injured in a shooting at a Colorado charter school, authorities said Tuesday afternoon.
The STEM School has about 1,800 students, the undersherrif said. At the time of this article, police consider the scene "active" and "unstable".
The sheriff directed parents to a recreational center to pick up their children.