Sahid Choudhuri, a member of the Manik Sarkar-led Left Front Cabinet in Tripura, had to resign in the wake of a police investigation inquiring into his links with HUJI pointsman Mamoon Mia. Choudhuri had issued a provisional residential certificate to Mamoon, the Bangladesh terror link who is alleged to have carried out several "assignments" in India.

As an immediate response to the disclosure, the party top brass has asked its elected representatives to inquire into details about the recommendations they have made or certificates they have issued to people, confirming residential proof. The word has been sent out from the highest level to all -- MPs, MLAs to panchayat heads.

Party MP and Central Committee member Md Salim said all elected representatives will have to verify details thoroughly before they sign on the concerned certificate. "We must all be cautious," he said. He added: "Choudhuri's resignation is a clear message to all party workers to be careful from now on."

In the CPM, an elected member only considers issuing a certificate of any kind to someone if the request for it has come from a local party worker. Salim said it is impossible for an MP or an MLA to know everyone in the concerned locality. They have had to depend on their party cadres.

In West Bengal, the Opposition has always raised allegations that the ruling CPM has made it easier for people from the other side of the border to settle permanently in the state in a bid to win votes. This practice has been rampant in the border districts of North 24 Parganas, Nadia, Maldah, Murshidabad and the three districts of North Bengal.

"Many Bangladeshi infiltrators legalised their habitation with these certificates. These illegal occupants have also been given ration cards and have regularly lifted their quota through the public distribution system. We realised this when the situation became complicated," said a senior leader of the CPM.