The teacher would have (and should have) reported it no matter what the color or religion of the kid in question. And Ahmed and his family know this perfectly well.
Irving PD statement
http://www.irvingisd.net/cms/lib010/TX01917973/Centricity/Domain/4/Media%20Release%20091615%20MacArthur%20Student%20Will%20Not%20Face%20Charges.pdf