Treutlen County's K through 12 school was locked down Thursday afternoon, Sheriff Tommy Corbin told 13WMAZ.
School officials found a .22 caliber rifle in a student's vehicle. A lock-down was initiated because of school policy, and the sheriff's office was called to search.
Corbin says deputies used drug- and bomb-sniffing dogs during the lock-down but found nothing inside the school.
A small amount of marijuana was discovered in the student's vehicle.
The student, a juvenile whose name was not released, was arrested and charged with possession of a firearm on school grounds and possession of marijuana on school grounds.
Multiple concerned parents called 13WMAZ to complain that the district did not tell them why the school was on lock-down.
An official from the Treutlen County school board refused to comment on the situation and said the superintendent is out of town and therefore unavailable for comment at this time.