The Enforcement Directorate has issued summons to four persons, including Ratna Chatterjee, wife of former Kolkata mayor Sovan Chatterjee and Shreya Pandey, daughter of state Consumer Affairs minister Sadhan Pandey in connection with the Narada tapes.
ED sources told news agency PTI on Saturday that the other two persons were Abhijit Ganguly and Moloy Bhattacharya.
While Ratna Chatterjee had been asked to appear on June 6, Shreya Pandey on June 13, Abhijit Ganguly on June 10 and Moloy Bhattacharya on June 11.
The Narada tapes allegedly indicted several Trinamool Congress leaders and ministers accepting cash for extending favour from a purported business in a sting operation.
The tapes showed the former mayor allegedly accepting cash and then wrapping it by a towel.
His wife had been called because Sovan Chatterjee had gone on record claiming Ratna Chatterjee was privy to all his financial transactions.