Narada sting: Videos allegedly showed leaders of Mamata Banerjee's party accepting bribes

The CBI has asked for the Lok Sabha Speaker's permission to prosecute four top Trinamool Congress MPs including Sougata Roy and Kakoli Ghosh Dastidar in connection with the Narada sting operation of 2016, in which many leaders are seen allegedly accepting wads of cash from a businessman.

CBI sources say the agency has written to Speaker Om Birla requesting sanction to act against Mr Roy, Ms Dastidar and Prasun Banerjee. Bengal Minister and former MP Subhendu Adhikari, who was an MP at the time of the sting, is also being investigated.

"We are yet to receive sanction. Once received, we will file the first charge-sheet in the Narada case naming the above four as an accused," a senior CBI officer told NDTV.

Sources say, 10 people seen on the Narada tapes have been summoned by CBI in Kolkata to come to its office and give a voice samples. Sovan Chatterjee is to appear on Saturday, Aparupa Poddar Monday.

In all, 13 people were seen Narada tapes, including seven MPs, four ministers, one MLA and an IPS officer. Of the 7 MPs, Sultan Ahmed died and Mukul Roy joined BJP in 2017. Of four ministers, Sovan Chatterjee joined BJP on 14 August.

Mukul Roy will not be named as an accused in the chargesheet, said sources, adding that the CBI would continue its probe against him. In the tapes, the sting operator offers Mukul Roy cash. Roy doesn't take any and tells him to deliver it in his office. Sources in the CBI say it does not enough evidence to seek his prosecution.

It is also not clear whether Sovan Chatterjee, a former Trinamool minister caught on camera, will face trouble. He joined the BJP on August 14. The CBI has summoned him on Saturday.

In 2014, Matthew Samuel, the CEO of Narada News, conducted a sting operation posing as a businessman and was seen in the tapes offering money to many Trinamool Congress leaders. It came to be known as the "Narada" scandal. The video clips, which surfaced before the 2016 Bengal election, allegedly showed Trinamool leaders accepting bribes. In 52 hours of footage, 13 people were seen taken a total of Rs 60.5 lakh.

Yesterday, Mathew Samuel was questioned by the CBI jointly with Trinamool Rajya Sabha MP KD Singh, who he claims funded the sting against his own party. "He specifically told me to focus on Abhishek Banerjee, Mamata's Banerjee's nephew," Mr Samual said after being questioned by the CBI.

The ruling BJP repeatedly targeted Bengal's ruling party with "Narada and Sarada (chit fund scam)" jibes while campaigning for the national election earlier this year.

The Trinamool, which has been stunned by the BJP's impressive haul in the national election - 18 of 42 seats - will take another major blow to its image if more of its members are arrested in the run-up to the 2021 state elections. In 2016, the Trinamool increased its seats in the state assembly. But this time, it is negotiating far more challenging circumstances, with the BJP making deep inroads on its turf.

On Wednesday, Chief Minister Mamata Banerjee had attacked the BJP, accusing it of using agencies to terrorise opponents.