Barrie police responded to Eastview Secondary School this afternoon, to assist staff with a student "slightly out of control."
The school was locked down as several officers arrived to the emergency call.
Principal Jane Seymour sent a letter home with students today to explain the school’s actions.
“This afternoon, one of our students became agitated and was using threatening language,” she wrote.
During the 30-minute lockdown, classroom doors were locked and nobody was allowed to enter or exit the school.
“This was done to keep the halls empty while we dealt with the situation,” Seymour said.
