This was done mostly by Gundas (gunde kee koi Dharm nahi hota), even in Punjab, Pak militants (wearing berd and Turban and create resemblance with Sikhs) have massacred hindus and Sikhs alike. That was done when Congress was in Power and for a congress leader who has tried to appease Sikhs by appointed Dr. M Singh as the PM. Its all a part of politics.
