Peel Regional Police have descended on a Mississauga high school.
Police are investigating at Clarkson Secondary School near Winston Churchill Blvd and Royal Windsor Dr after an email landed in the inbox of a small number of staff members.
Neither police nor the Peel District School Board will divulge the contents of the email, only saying it included 'non-specific' comments.
School board spokesperson Carla Pereira says classes are continuing as normal.
"Students and staff can exit and enter the building as they wish. However, we're asking them to do that through the main doors today and locking all other exterior doors of the building."