Raiganj: A case has been lodged against Mohit Sengupta, the Congress MLA of Raiganj, for allegedly plotting an attack on a Trinamul candidate and the murder of a ruling party worker during the rural polls.

Congress insiders see the move as a bid by Trinamul to mount pressure on Sengupta, also the North Dinajpur president of the Congress, to switch to the ruling party.

According to the insiders, Trinamul had used a similar ploy to engineer the defection of Congress veteran Manas Bhuniya after the 2016 polls. Bhuniya is now a Trinamul Rajya Sabha member.

Police sources said similar charges had been brought against 10 others. Anup Kar, the panchayat samiti candidate targeted on polling day on May 14, claimed Sengupta had "orchestrated" it. "We had filed a complaint against him and some others," said Kar, who won the seat. A police officer said searches were on to nab the suspects.