The FIR was lodged by Anjan Bera, a local leader of the Trinamool Congress, with Kotowali police station and a non-bailable case under the provisions of Arms Act was registered.
Superintendent of Police Sunil Chowdhury admitted that such a complaint was lodged and an investigation was on.
The 12 persons named in the FIR also included Bijay Paul and Satyen Maity, members of CPI(M) district secretariat.
Following a specific information, CRPF personnel dug a portion in the bank of a canal near a CPI(M) party office at Enayatpur and found 70 single barrelled guns yesterday.
Sources in the Trinamool Congress alleged that the CPI(M) was gathering arms to unleash terror during panchayat polls.