A 13-year-old student was caught with an Uzi submachine gun in his backpack at a secondary school in General Zuazua, Nuevo León, on Tuesday.

The 9-millimeter weapon was discovered as parents and teachers carried out a backpack search before school. The gun was not loaded.

Teachers took the student to the school’s administrative offices, and the school principal notified police and called the boy’s parents.

Identified only as Jonathan, the student said he had found the weapon in the street while walking to school that day. He was taken to the Attorney General’s Office in Monterrey so authorities could begin investigations into the gun’s origin.

The “Safe Backpack” operation had been applied randomly in Nuevo León schools since a 15-year-old student shot a teacher and three classmates at a school in Monterrey in January 2017. The student took his own life in the attack and the teacher died of serious injuries weeks later.

The operation was fortified recently after an 11-year-old student in Torreón, Coahuila, killed his teacher and wounded six people earlier this month, using two handguns he had taken to school in his backpack. The boy subsequently killed himself.

Threats of school attacks have increased in the state since the Torreón shooting. In some cases authorities have seized knives and identified the sources of the threats, mostly on social media.

Sources: El Universal (sp), Reforma (sp)