New Delhi, Sept. 15 -- The National Investigation Agency (NIA) has filed a charge sheet against three accused in connection with the March 15 grenade attack on a temple in Amritsar, which was allegedly carried out on the directions of foreign-based handlers, people familiar with the development said on Sunday. Two bike-borne assailants, Gursidak Singh and Vishal Gill, had hurled a grenade at Thakurdwara Sanatan temple at Chheharta, Amritsar on March 15 this year and it is suspected that Khalistan Liberation Force (KLF) operatives were behind the attack. The charge sheet filed on Friday before a special NIA court in Mohali named Vishal Gill, Bhagwant Singh and Diwan Singh. Gursidak Singh was killed in police encounter two days after the atta...