Kolkata, June 3 -- Trinamool Congress leader Anubrata Mondal, recently released on bail after nearly two years in Tihar Jail in a cattle smuggling case, is back under the CBI scanner after the premier agency started probing whether the Birbhum strongman has forced witnesses to change their testimonies.

The agency started reaching out to the witnesses after an audio clip surfaced online in which he was allegedly heard threatening a local police officer with sexual violence against the officer's mother and wife following which the district police filed a case against him.

CBI sources said the agency has explicitly advised witnesses to report any threats or attempts at mediation - either directly from Mondal or through intermediaries - immed...