Police are investigating after a loaded handgun was found in a 7-year-old boy’s book bag at a school in Far Rockaway, a law enforcement official tells NBC 4 New York.

The boy’s mom brought him to P.S. 215 Thursday morning, and came back to the school a short time later, claiming she needed to take him to a doctor appointment.

When she got back to the school, the loaded .22-caliber handgun was found and police were called. The school was then locked down for about 45 minutes.

It’s not clear exactly how the gun was discovered.

(Source: NBC New York)