Sebi had barred an Ahmedabad-based share trading company from trading in September 2011 for alleged market manipulation using Global Depository Receipts issues and initiated an enquiry against the firm.
"The DGM rank official of Sebi who was conducting investigation had issued show cause notice to the firm of the complainant.
"Meanwhile, the complainant came in contact with the middleman based in Mumbai who assured to get the work done in favour of the complainant, claiming close contact with the Sebi official," CBI said in a statement.
It said the middleman had allegedly demanded Rs 25 lakhs (Rs 2.5 million)
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