Montreal—Five minors were arrested and one will face charges after a hoax at a high school in La Prairie led to a tense lockdown on Thursday afternoon.

A 911 call was placed to the Roussillon regional police just before 3 p.m. from a phone booth inside of the Ecole de la Magdeleine. An anonymous caller reported gunshots inside of the high school.

Within minutes, 24 police officers rushed to the school in the small community on Montreal’s south shore.

“Students were barricaded in classrooms, which is standard, and police searched the entire building but it soon was determined to be a hoax,” said police spokesman Francois Michaud.

For an hour over 2,100 students and teachers sat beneath tables and behind locked classroom doors. One student reported that a “code white,” signifying a shooting, had been announced over the school’s public alert system.

“All measures were put in place to guarantee the safety of students and employees,” Principal Nathalie Berube wrote in a note to parents. “Thankfully it was a hoax.”

During the search that followed the warning, police identified five students as suspects and arrested them.

Two people were transported to hospital, at least one for fainting. A crisis unit was dispatched by the local school board to help students in distress following the lockdown.

The school caters to students in grades 10 and 11.

Four of the suspects were eventually released without charges, but Guy Lepine of the Roussillon police force say one youth will be charged. He was released after a legal promise to appear in court, and to not return to the school.