Billings Central Catholic High School instituted a modified lockdown Wednesday morning after a man who had been escorted off campus earlier in the day called into a popular radio show and announced that he was coming back.
He had been on campus first thing in the morning and was "wanting to discuss the end of the world with some of our students," said Principal Shel Hanser.
The man was escorted off campus. Later, he called into local radio program "The Big J Show" and announced that he was returning to the school to talk to the principal and try to set up an assembly.
"I'm gonna spread this knowledge to people," he said on the show. "It's not like a normal knowledge."
At that point, Hanser said, police were notified and the school was put in modified lockdown, which means students are kept out of the hallways.
Hanser also closed the campus for lunch, requiring students to stay at the school to eat.
The man never returned and the students were never in any danger, Hanser said.
"We're pretty much business as usual now," Hanser said later in the afternoon.