The Sandeshkhali sting exploded in the middle of the polls, with the BJP deciding to adopt a two-pronged strategy to counter the Trinamool's charges that the alleged incidents of sexual assault in the North 24-Parganas island were part of the saffron camp's conspiracy.

The purported sting, the veracity of which has not been verified by The Telegraph, surfaced on Saturday. The video shows Gangadhar Koyal, a BJP Mandal president in Sandeshkhali-II, admitting that no rape or sexual harassment had taken place in Sandeshkhali and women were persuaded to file such complaints at senior BJP leader Suvendu Adhikari's behest.

The BJP has decided to take recourse to legal avenues — including a complaint lodged with the CBI — to counter the charges, and plans to tell people that the video was "morphed and edited" to malign the party.

On the sidelines of a poll rally in Nadia's Nabadwip on Saturday evening, Adhikari fumed: "The video is manufactured by Abhishek Banerjee, I-PAC’s Prateek Jain and a man who runs a news portal. These people have done it. But people will not accept it as true. Gangadhar Koyal (the BJP worker purportedly speaking in the video) has submitted a written complaint before the CBI director seeking an inquiry. He is going to the CBI office to file a complaint against Abhishek Banerjee. We will go to the maximum extent on this issue."

The entire Trinamool ecosystem, including chief minister Mamata Banerjee and the party's second-in-command Abhishek, went to town to nail the BJP on the issue that had Bengal's ruling party rattled ever since reports of local Trinamool leaders indulging in land-grab and sexual assault emerged from Sandeshkhali in February.

A livid Adhikari on Saturday called it a "conspiracy". The faces of the protest in Sandeshkhali are women. There were at least 379 complaints apart from some separately lodged with the police and court at the initiative of (BJP leader and lawyer) Priyanka Tibrewal … Police have started three rape and molestation cases. So all these are lies? They (Trinamool) have made this video fearing defeat."

However, Koyal had done the damage while speaking to a TV channel earlier. "I am visible in the video. It's my voice in the video but it was tampered with," he said.

No top BJP leader from Delhi has so far reacted to the alleged sting. However, it has dealt a blow to the BJP as party leaders, including Prime Minister Narendra Modi and Union home minister Amit Shah, who have been pivoting their Bengal Lok Sabha poll campaign around Sandeshkhali.

At a public meeting in the run-up to the polls in Barasat in March, Modi said: "The Sandeshkhali storm will sweep across Bengal and ensure an end to Trinamool's rule of terror."

On Modi's advice, the BJP also formed the Maa Durga Shakti Swaroopa Prachar Prasari — a 300-member team of Sandeshkhali women — to campaign across all 42 constituencies in Bengal. It also fielded an alleged victim, Rekha Patra, as its Basirhat candidate.