Police in Ottawa, Canada are investigating an antisemitic incident that occurred at Sir Robert Borden High School on December 1.

In a letter sent to parents, the school’s principal Matthew Gagnier described the incident as a “blatant act of antisemitism, which is absolutely unacceptable,” the Ottawa Citizen reported.

According to the letter, students who had stayed after school were asked to go into a room where they discovered the swastika. When they noticed it, another student made a Nazi salute.

“Every student deserves the right to feel safe at school, regardless of religion/creed, race, background, ability, gender or sexual orientation,” Gagnier wrote.

He added that the students behind the antisemitic act will face disciplinary and educational measures.

But, according to the report, parents criticized the letter for being sent to them after some time had passed, at which point they had already heard about the incident from their children and other parents.

The Ottawa-Carleton District School Board (OCDSB) and the Ottawa police have launched investigations into the incident. Police said that the incident was reported to them on December 5. The investigation is being run by the hate crime and bias unit.

The CEO of the Jewish Federation of Ottawa, Andrea Freedman, told the Citizen that there have been so many antisemitic incidents in local schools in the last year that they have hired an antisemitism specialist who is focused on combating antisemitism at OCDSB schools.

“Parents are not equipped to handle this. They see their children being harmed, but don’t necessarily have the advocacy tools,” she said.