CHICAGO (CBS) — Students at an Indiana high school are rallying behind a beloved teacher who could be fired after failing to report a man on school grounds with a gun.

The incident happened at Lake Central High School in Saint John, Indiana.

The man who walked into the school angry and armed is a convicted felon and now faces possible criminal charges. The teacher, who kids say made sure they were safe, could lose his job.

Students from Dennis Brannock’s class lined up to support their teacher who taught auto shop at Lake Central for 45 years.

“Mr. Brannock is a wonderful teacher. He goes above and beyond,” stated Nick Reifinger, a high school junior.  “I don’t think it is fair.”

Brannock could be fired for not reporting an armed man in the school and around his students.

“Mr. Brannock didn’t see the gun, didn’t know he had a gun,” said Mo Sharawi, a high school junior.

On September 21, Mo Sharawi, as part of the auto shop class, took his car on a test run through a nearby neighborhood. Soon after, an irate man with a gun followed him back to school, went through the shop doors inside the school, accusing him of driving recklessly around kids.

“I would never drive that fast in a small neighborhood,” Mo Sharawi said.

Students say the man took his gun back to his car, then came back again, yelling at the kids. Students say Brannock became aware of the situation and stepped in.

“He locked the doors, turned off the lights, and sent us to another classroom,” recalled Sharawi.

Brannock failed to report the incident to the principal or to the Saint John Police, who only found out about the incident after a concerned parent called them.

As police investigate possible criminal charges against the armed man, the school board said they are following board policy, which specifically states that staff members must report knowledge of weapons or threats against students to the principal and “failure to report such information may subject the staff member to disciplinary action up to and including termination.”

Students hope that is not the case.

“Mr. Brannock did a great job of handling that. I don’t think he should be in this situation or even be getting in trouble for this,” said high school senior Cory Middleton.

Students and some community members are planning to rally in support of Brannock before a school board meeting Thursday night.