BLOUNTSVILLE, Ala. (AP) — Police arrested a substitute teacher in Alabama on Friday after his gun went off in a first-grade classroom.

No one at Blountsville Elementary School was injured in the incident. But authorities tell news outlets that Henry Rex Weaver, 72, is in custody and will face charges.

Blount County Sheriff Mark Moon said students were in the classroom with Weaver when a gun that was in his pocket discharged.

"It (the sound) alerted administrators," Moon said. The sheriff said Moon was detained and later jailed.

Blount County District Attorney Pamela Casey said Weaver will face charges of reckless endangerment, third-degree assault and possession of a firearm on school grounds, Al.com reported.

"Obviously I'm concerned about a substitute teacher bringing a gun to school, and what we can do to prevent that in the future," Moon said.

Records aren't yet available to show whether Weaver has a lawyer who could speak on his behalf.