Acting on a tip-off, the police had arrested four persons on July 25 last and after interrogating them, five others were arrested on August 5, Cooch Behar SP Rajesh Kumar Yadav said.
Two 9-mm pistols, one gun, three 303 cartridges, seven 9-mm cartridges and a vehicle were recovered from them, he said.
The arrested persons were associated with several incidents of dacoity and criminal activities including kidnapping of a polytechnic teacher of Kokrajhar in Assam, Yadav said adding, they were also associated with militant outfits like NDFB and Birsa Munda Commando Force.