Four Maoists were killed in an encounter with police at Sundermahto village in the district, police said on Sunday.
A gunbattle ensued after a police team in plain clothes challenged the extremists following a tip off by an arrested Maoist Arjun Yadav on Saturday evening, Superintendent of Police Praveen Kumar Singh said.
Two Maoists tried to snatch the pistol of officer-in-charge of Vishnugarh, Bhola Prasad Singh, who managed to fire a shot killing one of the extremists, before other policemen came to his rescue.
Arjun Yadav, who had guided the force to the spot where the Maoists had assembled, fell to the bullets as he tried to escape. Yadav had been arrested on Friday in connection with the killing of MLA Mahendra Pratap Singh in 2005.
Two other Maoists were also killed in the firing, the SP said. They were identified as Nitish, self-styled sub-zonal commander of the outfit, and Rashmi.
A woman cadre of CPI (Maoist) Kanti was arrested, the SP said.
Police recovered two guns, one pistol and a 30-kg landmine from their posession.
The Maoists had gathered there reportedly to distribue money extorted from contactors of NREGA projects and Kendu leave collection.