Kolkata: Trinamool Congress leader Anubrata Mondal on Wednesday said he wanted a CBI probe into a threat letter against a judge of Asansol special CBI court who is hearing the alleged cattle smuggling case against him.

Asansol special CBI court judge Rajesh Chakraborty wrote to Paschim Bardhaman district judge on Monday requesting him to take note of the "threat" and bring it to the notice of the Registrar, Judicial Service, of the Calcutta High Court.

"I want to request the judge to order a CBI investigation into it," Mondal said in reply to questions by reporters about the threat letter while he was being taken to the Asansol special CBI court for production.

"A letter threatening to implicate his family members in NDPS case of commercial quantity if Mondal is not released on bail soon was sent to the officer-in-charge of the court," judge Chakraborty wrote to the district judge.

Asked whether he is hopeful to get bail, the TMC Birbhum district president said it is for the court to decide.

"Mamata Banerjee has done a lot," Mondal said when asked whether he wants to send any message to the chief minister.

Banerjee, at a public meeting on 14 August in Kolkata, had stood by Mondal, asking what he had done to be arrested by the CBI.

She had alleged that agencies are being used to malign whom they want to.

CBI is probing a cattle smuggling case, in connection with which it has made a number of arrests, including Mondal on 11 August.

He has been in CBI custody since then.