The teenager has also been charged with trespassing at the school, said Marc Limansky of Anne Arundel County, Maryland, police.
Authorities said Monday that they would have a visible presence at county schools after the threats.
On their website, Anne Arundel County Public Schools said that there were “no known credible threats at any county school,” but that they “take every report of every threat seriously” and that the increased police presence would last the week.
The threat stemmed from a fight at the school, said Limansky, who didn’t know whether the teenager charged was a current student.
There had been reports of threats at three other county high schools, but Limansky said none of them were credible and that at least one of those reports was based simply on a query from a student wondering whether their school had been threatened.
“When a student sees this kind of thing,” Limansky said, “their instinct is to repost it, and that’s about the worst thing you can do, because the only effect it has is, it creates anxiety and fear. … [We] have the best opportunity to locate the original poster, the source of that information.”
His advice to any student who sees what they think is a threat online: “Contact the police immediately. Don’t share it, because it just gets completely out of hand.”
Like WTOP on Facebook and follow @WTOP on Twitter to engage in conversation about this article and others.