MOHALI (PUNJAB): The NIA on Tuesday filed a charge sheet against eight terrorists of the outlawed Khalistan Liberation Force (KLF) for their alleged involvement in killing Shaurya Chakra awardee Comrade Balwinder Singh Sandhu at the direction of their Pakistan-based handlers, an official said. Sandhu, who fought terrorism in Punjab, was shot dead in October last year in Tarn Taran district. The charge sheet, according to which Sandhu was killed by the KLF terrorists, was filed before a special National Investigation Agency (NIA) court in Mohali under relevant sections of the Indian Penal Code, the Arms Act and the Unlawful Activities (Prevention) Act.