It is indeed very unfortunate that militants have chosen a soft target to perpetuate a very heinous act. It was also unfortunate on the part of media and police to name certain terrorist organizations without proper investigation.
Yes; it could have been a Muslim terrorist organization, but without proper investigation and proof accusing them will unnecessarily create discontent among Hindus and Muslims.
Let the investigating agencies do a sincere job, book the culprits and punish them, which certainly will be acceptable to all sections of the society.