CBI is investigating the case to find out who had instructed Mr Mirza to take the cash offered to him.

Senior IPS officer SMH Mirza appeared before CBI officials today for questioning in connection with its probe into the Narada tapes case.

According to a senior officer of the agency, Mr Mirza, who had appeared before CBI officials for interrogation on June 6, was called today for another round of questioning in connection with the investigation.

CBI sources said that Mr Mirza could be asked about his connections with the then Trinamool Congress leader Mukul Roy, who is also allegedly involved in the scam.

Mr Mirza was the Superintendent of Police of Burdwan district when the sting operation was conducted by Mathew Samuels of the Narada News portal.

The CBI is investigating the case to find out who had instructed Mr Mirza to take the cash offered to him and on whose behalf, sources in the probe agency said.

In the sting operation, which was claimed to have been carried out in 2014, some persons resembling senior Trinamool Congress leaders and the IPS officer are seen accepting money from the representatives of a fictitious company in return for favours.

However, the sting video footages were uploaded in the news portal before the West Bengal Assembly elections in 2016, creating a furore in the state politics.

Taking over the investigation of the case following a Calcutta High Court order, the CBI had booked 12 top TMC leaders, including MPs and West Bengal ministers and Mr Mirza.