Three high school students in Alabama were arrested Friday after investigators received an anonymous call that a loaded gun had been brought to campus.

“The person who called in the tip is a hero,” Dallas County Sheriff Mike Granthum told WFSA-TV.

Granthum said officers put Southside High School into lockdown and went to a specific classroom, based on information from the caller.

The sheriff said officers found handguns inside a bag and one inside a jacket. All three weapons were loaded.

One student was charged with possession of two guns, the other was charged with possession of one, the sheriff said.

While continuing to search the classroom, deputies found a third student who faced a “pick-up” order, which is an arrest warrant for a juvenile. Granthum said that student was wanted for an unrelated incident involving a shooting into an occupied vehicle or dwelling.

All three students were taken to a juvenile detention center.