FAIRFAX, Va. (AP) – A 12-year-old is charged in northern Virginia with threatening her school with a social media message using emojis of a gun, a bomb and a knife.

Emoji symbols, used on mobile devices, sometimes replace words.

The Washington Post reports the student at Sidney Lanier Middle School in Fairfax posted an Instagram message in December. It contained the words “Killing” and “meet me in the library Tuesday.”

According to a search warrant, the girl acknowledges she posted the messages under another student’s name. She’s charged with threatening the school and computer harassment.

Her mother says the girl posted the messages in response to being bullied in school, and is “a good kid’ who’s “never been in trouble.” The mother says the girl shouldn’t have been charged.