BRIDGEWATER (CBS) – A teacher pulled a fire alarm at Bridgewater-Raynham Regional High School Wednesday morning after hearing “concerning comments” from a student about a gun, the superintendent said.

Officers went to the school around 8:15 a.m. after getting a 911 call that there were students evacuating the building. It was at that time police learned that someone had pulled the fire alarm. It was later discovered that a teacher pulled the alarm “after two teachers overheard what they thought was a student making a mention of a gun in a hallway,” police said in a statement.

The school was evacuated and later cleared by officers. No gun was found. Everyone was allowed back inside and classes resumed around 9 a.m. Parents were told about the incident in a phone message. No arrests have been made.

“At this point we do not know exactly what was said or who may have said it and that remains under investigation,” Chief Delmonte said in a statement Wednesday afternoon.

“We’re speaking to students that were in proximity to the classroom where the comments were heard and students that were in the classroom itself,” Superintendent of Schools Derek Swenson told reporters at a news conference.

Swenson praised the teacher for pulling the alarm.

“I think the teacher definitely acted responsibly in terms of, in the eyes of safety, at that point, hearing that comment and then wanting to make sure that students and staff were notified of some type of an emergency so that they would then evacuate,” he said.

It was the last day of school for seniors. They didn’t think they would leave on high alert.

“It was just an interesting last moment to happen on a last day of school and it was just out of the blue and it was just crazy,” one student said.

Questions remain about what actually happened.

“I probably heard two or three different stories and that’s just me,” another student said. “You know there’s probably some people who have heard four or five.”

The teacher has not been identified. No one was hurt.