More than 1,000 students in Ellicott weren’t in school on Monday because of a violent threat that was posted on an app called “After School.” School leaders considered the post a "significant, violent threat" so they closed the entire school district.
Investigators have since identified the suspect behind the threat, but they’re not releasing any more information.
School officials say District 22 will be back open on Tuesday.
KRDO took a closer look at the “After School” app, which allows students to make anonymous posts. The app shows videos of students saying, "The thing I love most about after school is, well, who doesn't want to know what people actually think about them," and, "I use After School to see what people are saying about others."
The El Paso County Sheriff’s Office says the students using the app are not as anonymous as they think. The app company collects students’ personal information, such as their IP address and their location.
KRDO spoke with a woman in Ellicott, Randie Balle-Mason, who says she had to call out of work to stay home and babysit her grandchildren, who were supposed to be in school. "The whole reason my family lives here, is because it's supposed to be safe. I think the app is a very dangerous place to go. If you have an app where you can just say anything. You can threaten people and not be held accountable," Balle-Mason said.
A spokesperson with "After School" says the company has a system set up to help catch harmful posts before students see them. They also say the threatening post was detected by the company's moderators.
Copyright 2016 KRDO. The Associated Press contributed to this report. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.