Niwot High School in Boulder County, Colo. is closed Friday as authorities investigate a threat to blow up the school and a 30-name "hit list."
A threat that the school would "blow on the 11th" was found scrawled on a bathroom Monday and made public Tuesday. Officials decided to close the school when the threat escalated upon Thursday's discovery of the threatening hit list filled with students' names, The Longmont Times-Call reports.
Parents were notified of the decision and investigation in a letter Thursday. Deputies are using dogs to comb the school for bombs, and the school is offering a $1,000 reward for anyone with information about the perpetrator.
"We made a recommendation to the school district that they don't have school on Friday for safety reasons, for the students," Cmdr. Rick Brough of the Boulder County Sheriff's Office told KUSA-TV. "It gives us more time to do an investigation and see if we can identify who is responsible, and whether the threat is credible."
Schools across the country are still on high alert as parents nervously sent their children back to class after the Dec. 14 Sandy Hook school shooting. Districts nationwide have tightened security measures and increased campus patrols, and hypersensitivity to any unusual activity or perceived threats have already resulted in numerous lockdowns.
"Ten years ago this wouldn't have been a problem, and now it’s a real problem. And my child’s name is on the list, and it’s very concerning," parent Ellen Ross told TheDenverChannel. "I just really hope that the parents talk to their kids and try to find out what is going on because some child knows. No child does this and doesn’t tell anybody. I really want the parents to talk to their kids and find out who’s doing this."
Weekend activities, including a girls' basketball game and wrestling tournament, have also been canceled, KDVR reports.
CORRECTION: A previous version of this story incorrectly stated that Niwot High School is located in Boulder, Colo. The school is actually in Boulder County, Colo. We regret the error.
ALSO ON HUFFPOST:
Don’t miss out — be the first to know all the latest and breaking news. Learn more