CHICAGO (AP) — A suburban Chicago high school student has been arrested after posting photos on social media showing him holding an assault-style rifle.

The 15-year-old was arrested Sunday, charged as a juvenile with a felony count of disorderly conduct and taken to the Juvenile Temporary Detention Center in Chicago.

The Cook County Sheriff’s Department reported at least one of the photos had a caption making an apparent threat against Alan B. Shepard High School in Palos Heights.

No weapons were found in the boy’s home in Worth. The photos were taken elsewhere, with the weapon belong to a person with a valid state Firearm Owners Identification card.

Shepard Principal Greg Walder said Thursday the photos were discovered by a student who told a parent who passed on the information to school officials.