It happened June 6 around 3 p.m. at the Atlantic Community Charter School in Galloway Township, New Jersey.
Police say a 7-year-old child unknowingly brought a loaded 9mm handgun to school in a backpack.
According to police, the child's relative, Lamar Keith Williamson, allegedly put the gun in the backpack.
Williamson was arrested
He is facing charges of endangering the welfare of children, unlawful possession of a weapon and possession of a weapon by a prohibited person.
Police say there was no danger to the students.
Anyone with any information is asked to call police at (609)- 652-1234.