The Instagram video shows a teenage girl, her fingernails painted white, holding a handgun with bullets spilled across a table. “You ready for your first and last day of school?” asks the caption.
Alarmed parents reported the video, posted at 9 p.m. Sunday before children in Orem, Utah, returned to school Monday, to police, reported The Daily Herald.
Police arrested the girl, a 17-year-old senior at Mountain View High School, on suspicion of terrorism, disorderly conduct and possession of a handgun by a minor, reported KSL-TV. She told officers the handgun belongs to her mother, the station reported.
“This is no joke folks,” Orem police wrote in a Twitter post that included a shot from the Instagram video. “Talk to your kids about how serious of a crime this is (joking or not)!”
The gun has been confiscated, police wrote on Twitter.
Lt. Craig Martinez told KSTU the girl was arrested within 90 minutes of posting the video to Instagram after teenagers alerted their parents.
“We applaud the courage of those kids who saw her post and talked to their parents, who in turn talked to us,” Orem police wrote on Facebook. In the video, the girl loads a magazine into the gun, then points it at the camera and pulls the trigger, police wrote.
A police officer was posted at the high school Monday for the first day of class, reported The Daily Herald.