The CBI on Saturday conducted raids at residences and offices of flamboyant liquor baron Vijay Mallya and his now-grounded Kingfisher Airlines in connection with a Rs.900 crore loan to the airline by IDBI bank and now declared a non-performing asset (NPA).

The raids were conducted at five places - at offices of Kingfisher Airlines and at the residences of Mallya and others in Bengaluru, Mumbai and near Panaji, said Central Bureau of Investigation officials (CBI).

A CBi spokesman in New Delhi told IANS in the afternoon that that the raids were still on at five places of Mallya's offices and residences in Mumbai, Bengaluru and near Panaji in a case of allegedly violating banking norms in sanction and disbursement of Rs.900 crore to Kingfisher Airlines.

In Goa, a CBI team from Mumbai raided the Kingfisher Villa, Mallya's expansive property in the tony Candolim beach area, located 15 km from Panaji.

The CBI had registered the case against Mallya, Kingfisher Airlines chief finance officer A. Raghunathan and unknown officials of the IDBI for allegedly violating banking norms in sanctions and disbursement of credit limit of over Rs.900 crore.

The loan was advanced by the IDBI bank despite the fact that there was uncertainty about huge loans earlier extended by a consortium of banks to the airlines being paid.

Some of the banks in the consortium have already declared Mallya as a "wilful defaulter".

Sources said what raised suspicion was the fact that it was the first exposure of the Kingfisher to the bank and the big loan was granted despite negative rating and net worth of the airlines.

While registering the preliminary enquiry in 2014 into the questionable sanction of loan by IDBI, the CBI had said: "There was no need for the bank to take the exposure outside the consortium when already other banks loans were getting stressed."

A string of Indian banks have an exposure of nearly Rs.7,000 crore in loans to the airline, with the State Bank of India leading with Rs.1,600 crore.

A consortium of 17-state-owned financial lenders led by SBI was formed to recover the money from the airline company.

Debt-ridden Kingfisher Airlines was virtually grounded on October 1, 2012 as the passenger carrier cancelled all 50 flights after a section of its employees went on strike leaving thousands stranded. It lost its operator's licence on October 20, 2012.

The Kolkata-headquartered United Bank of India (UBI), which was owed Rs.400 crore by Kingfisher, first declared Mallya a wilful defaulter in May 2014. But Mallya's lawyers managed to convince the Calcutta High Court in December that the process of declaring him so was faulty.

However after apex bank Reserve Bank of India (RBI) extended the ambit of the term "wilful" defaulter to include not only the primary defaulting entity, but also the guarantors of its loans, and individuals on the boards of companies declared to be in wilful default, Mallya was again declared a wilful defaulter this year,

Mallya owns a 'Hollywood' style Kingfisher Villa at Candolim in Goa. Another prime property is Kingfisher House, measuring 17,000 square feet in Mumbai's suburban Andheri locality. Reportedly, the property was originally hypothecated to Punjab National Bank in 2010.