BENTON, Mo. (AP) — A man has been charged with unlawful use of a weapon and child endangerment after police say he used a handgun as a hammer while working on a project at a southeast Missouri elementary school.

A probable cause statement from the Scott County Sheriff’s Department said 45-year-old Jeffrey Grubbs was a volunteer at a 4-H event Monday at Kelly Elementary School in Benton when he gripped the handgun’s barrel and used the butt of the weapon to drive a thumbtack into a wood plaque.

The Southeast Missourian reports Grubbs was arrested and released Tuesday. Police say Grubbs has a concealed-carry permit, but it’s illegal to bring a gun onto school property without consent from a school official.