The FIR has been lodged against the former legislator under section 354 (outrage of modesty) of the IPC and Section 8 of Protection of Children from Sexual Offences Act, 2012 at Birganj police station of Gomati district, a senior police officer said.
A minor girl was allegedly sexually abused by the ex-MLA in a party office at Amarpur on November 27 last.
After coming to know of the incident from her daughter, the mother of the girl informed the matter to the CPI(M) state unit secretary Bijan Dhar few days back.
Since the incident is related to a minor girl, the Officer in Charge (OC) of Birganj police station had registered a General Diary (GD) suo motu and started investigating the incident.
Based on the inputs of the probe, an FIR has been lodged against the former MLA to pave the way for an elaborate investigation into the case.
Opposition parties, the Congress and the BJP, have already demanded immediate arrest of the former MLA.