Peel Region police Const. Fiona Thivierge says two more students — aged 16 and 17, both boys — are under arrest and another, a 16-year-old boy, is still being sought.
She says police were called to St. Roch Catholic Secondary School in Brampton, Ont., just before 11:30 a.m. and promptly placed it under lockdown.
The lockdown has ended after police determined the third suspect is not in the school.
And other schools in the area are no longer in hold and secure mode.