The threat came in an Instagram comment, and read, "Watch out, I'm coming" -- followed by three emojis: a gun, a knife and a bomb.
And even though the sender appears to be a young student who was fed up with bullying, the threats are serious enough to have caught the eye of investigators in Fairfax, Virginia.
After a school resource officer spotted the threats, police filed a search warrant and traced the threats back to a girl at Sidney Lanier Middle School. The warrant says the comment threatened death or bodily injury to other students.
Among the posts posted by the made-up Instagram account was a "hate list" that named several middle-schoolers. The threats said an attack was planned for Dec. 15, when students were still in school.
Police charged the student with a felony. They seized a cell phone from her home, including login information for social media accounts.
Her mom said she didn't believe her daughter would have carried out any of the threats. She was just sick of bullying.
"It was just too much, she couldn't handle it anymore," said the mom. News4 is concealing her identity to conceal the identity of the girl, who is a juvenile.
Washington, D.C., Maryland and Virginia local news, events and information
"It wasn't just one boy, it was a group of boys bothering her," the mom said.
"As a mom, I don't know what to tell you," she added, the worry for her daughter and frustration over what she did obvious in her voice. "She wasn't thinking like an adult, you know we all make mistakes."
Threats are taken seriously by school authorities, who said that the number that they hear about is increasing.
Wednesday, Fairfax County issued a statement:
"Last week, FCPS became aware of a potential threat directed at Lanier Middle School that was posted on social media. Fairfax City Police identified and interviewed the individual who posted the threat and determined the threat was not credible. The Lanier community was also notified of the issue.
"The safety of our students and staff is our highest priority and we take all threats seriously. FCPS encourages all our students 'when they see something - to say something' and we work closely with law enforcement when such threats occur.
"Unfortunately, these kinds of anonymous threats can be concerning and disruptive even when they are not credible. We ask parents to speak with their children regarding the serious consequences that can result from the inappropriate use of social media."