The National Investigation Agency (NIA) has filed a supplementary charge sheet against four top leaders of the banned CPI(Maoist) in a case related to the brutal killing of a civilian in Bihar five years ago, an official said on Saturday.

The accused charge-sheeted on Friday in the NIA Special Court, Patna (Bihar) under relevant sections of IPC, Arms Act and UA(P)A have been identified as Ram Prasad Yadav, Abhijit Yadav and Abhyash Bhuiya alias "Prem Bhuiya" of Jharkhand and Subedar Yadav of Bihar, a spokesperson of the central agency said. The official said all of them are senior leaders of the proscribed outfit CPI (Maoist).