New Delhi: Fugitive diamantaires Nirav Modi and Mehul Choksi had used a web of shell companies registered in Belgium, the UK, Hong Kong and Dubai to siphon off the loaned money, some for round-tripping to India as well as to funnel it to tax havens from where recovery would be next to impossible.

Investigators from the Enforcement Directorate probing the Rs 12,300-crore bank scam perpetrated by Modi have found the money taken against fraudulently acquired letters of credit were siphoned off using more than 50 dummy shell companies.

While some of the money came back to India, possibly to be invested in more risky but high-return ventures such as stock markets and realty, some of it were siphoned off through a web of banking channels to tax havens.

Earlier, The Telegraph had reported that Nirav Modi had registered a dummy company Nirav Modi BVBA in Antwerp five years back with his brother Neeshal Modi as manager.

Officials said they were approaching the Dutch authorities to seize the accounts of the firm as well as that of another dummy firm.

Similar shell firms and bank accounts have been found in Hong Kong, London, Dubai, which are being probed, said the officials.

Nirav and Neeshal Modi grew up on the streets of Antwerp where their father had a diamond shop. The city and its diamond district are no stranger to the duo and many claim that they may well have stayed there after fleeing India in the wake of the discovery of their bank fraud.

Though New Delhi is believed to have requested the Hong Kong administration to locate and hand over Modi and Choksi to the Indian authorities, many investigators believe they could well have relocated to the European state or to a tax haven island with which India does not have an extradition treaty or even a mutual legal assistance treaty.

Rumours that Nirav Modi had sought the citizenship of Nevis & St Kitts, a Carribean island nation, with which India has no extradition treaty has, however, been denied by the island nation.

Another diamantaire fugitive Jatin Mehta of Winsome Diamonds is rumoured to be holed up in the island nation.

The recent arrest of Modi aide Shyam Wadhwa has helped investigators to unravel part of the paper trail which Nirav and Choksi left behind.

For instance, Aura Gems, a Modi-linked company based in Hong Kong transferred Rs 468 crore to Diamond R US, Stellar Diamond and Solar Exports in India soon after a PNB letter of understanding (LoU) was encashed in the island nation.

The transfers were often shown as unsecured loans among group entities.

Incidentally, Aura Gems was set up by another shell company registered in the Briitsh Virgin Islands.

A clutch of overseas companies — Aura Gem Company, Sino Traders Co, Unity Trading, Sunshine Gems, Tri Colour Gems and Pacific Diamonds — were among the recipients of the money paid by Indian banks against the LoUs fraudulently obtained from PNB by Nirav Modi and his associates.

Though Modi was ranked by the Forbes magazine as India's 85th richest with a net worth of $1.74 billion last year and his firm Firestar Diamond became better known as the jeweller to Hollywood stars such as Naomi Watts and Kate Winslet, he remains a person off the global radar. Despite lookout notices sent out through Interpol, no real evidence of his whereabouts has emerged.