NEW DELHI, March 8 (Xinhua) -- India's Central Bureau of Investigation has launched a fresh case against billionaire jeweller Nirav Modi and top officials of his companies in connection with the country's biggest-ever bank fraud of 1.8 billion U.S. dollars.

"This is the third information report (FIR) lodged against Modi and top executives of his Firestar group for defrauding the state-owned Punjab National Bank by availing different credit facilities between 2013 and 2017," a senior official said Thursday.

An FIR is the first and the most important document to initiate criminal proceedings. And all the three FIRs have clearly established the fraud of 1.8 billion U.S. dollars, he added.

But Modi is yet to be arrested by Indian investigators who have so far taken into custody nearly 20 people, including some senior executives of companies owned by the jeweller and his uncle Mehul Choksi as well as high-ranking officials of the Punjab National Bank, in the probe.

While India's External Affairs Ministry has revoked Modi's passport as well as his uncle and business partner Mehul Choksi's for their involvement in the scam, law enforcement authorities have seized 10,000 luxury watches and nine luxury cars, apart from freezing his bank accounts.

Modi is said to have defrauded Punjab National Bank, India's second largest state-run bank, of 1.8 billion U.S. dollars, though he has said that he owed the bank only 775 million U.S. dollars, in a letter shot to the bank's management.

The celebrity jeweller - the mastermind of the massive fraud - is said to have fled the country and was reportedly last seen in New York after his appearance at World Economic Forum in Davos as a part of an Indian delegation.