A 13-year-old girl was arrested in Mesa County Tuesday after reportedly threatening to use a gun on school grounds.
Students told administrators at Mount Garfield Middle School that the girl posted images of a handgun on Facebook.
The weapon has not been found and remains the primary focus of the investigation, deputies said.
The girl from Palisade is facing charges related to felony menacing, unlawful possession of a firearm by a juvenile, interference with students at a school and harassment.
The student's identity is not being released at this time.
"The students who reported this dangerous behavior should be commended for coming forward about the social media posts related to their school," investigators said.