The Al-Huda Elementary School in Mississauga on the outskirts of Toronto, was closed for fear of a backlash. This Muslim school is the sister institution of Pakistan's Al-Huda Institute in Multan where California shooter Tashfeen Malik studied.
Controversial Pakistani female Islamic scholar Farhat Hashmi, who is the founder of the Al-Huda Institute in Multan, started this Canadian branch in 2004.
The four girl students -- in ages between 16 and early 20s -- from this school travelled to Syria in recent years after completing their studies, according to Canadian security agencies.
While three girls were intercepted in Turkey, the fourth is in Syria.
"It's really scary and it's really dangerous -- and if she gets caught she will get killed," the sister of the woman in Syria told the Canadian Broadcasting Corporation.
School manager Imran Haq said: "The Institute has no knowledge as to the identity of these individuals and as such cannot confirm whether or not they were enrolled in the Institution, for how long, or any other related information."
He said the school was closed because of "a fear of backlash".
The school has 160 students in classes from kindergarten to grade six. It also offers adult classes in the evenings and on weekends.