Etwari Hembram alias Nareshda was arrested yesterday and six others Maoists, including two women, were caught on his information, SP Prabhat Kumar said.
Kumar said Hembram was involved in the 2014 ambush on a police vehicle in which Balihar and several other policemen were killed at Kathikund in Dumka district.
Hembram was also involved in a landmine blast in the state in 2014 in which four policemen were killed and in the encounter at Sundar Pahari in Godda in which two policemen were killed, the SP said.
Police recovered naxal literature, uniform, clothes, remote control, medicine, pouches and walkie talkies from them.