The CBI, on 13 December, arrested an alleged hawala operator - KV Veerendra - in connection with the seizure of Rs 5.70 crore in Rs 2,000 notes, from his premises in Karanataka.
The agency sources said that the CBI has registered a case against officials of four banks--State Bank of India, State Bank of Mysore, ICICI Bank and Kotak Mahindra Bank.
They said Veerendra was produced before the Special Court in Bengaluru, which has sent him to six days of CBI custody for questioning.
Sources said that during the preliminary probe, names of several persons have been mentioned by Veerendra and it is trying to gather material evidence linking the alleged hawala operator with them.
Sources also said that during the six days of questioning, CBI will confront him with documents recovered from his premises and will try to get the source of these funds which may unravel alleged involvement of senior bank officials in the case.