Although the location is never clearly stated, Principal Kirkpatrick, played by Bruce Willis, has the state flag of New Jersey in his office. Willis grew up in Penns Grove, New Jersey.
The deleted scenes show multiple references to John Wilkes Booth, which frames the scene where the rooftop shooter jumps down from the roof and limps away on one leg.
The screenplay for this film was featured in the 2006 Blacklist; a list of the "most liked" unmade scripts of the year.
When Principal Jared explains the Arabic word "La Hariq" meaning, he says it means don't shoot, However it actually literally means "No Fire"; whereas don't shoot is either "Ma Titliq El Nar" or "Matedrabsh Nar" depending on the dialect spoken, considering he heard it near Tigris, the first variation would be more likely. This mistake is likely due to using generic literal translators.
Reunites Bruce Willis with Mischa Barton after The Sixth Sense (1999), although they share a few moments together.