NEW DELHI/MUMBAI — India’s federal investigating agency said on Tuesday it has arrested six people in an alleged $1.8 billion bank fraud case that continued for six years.

Central Bureau of Investigation spokesman Abhished Dayal said five bank workers and an employee of suspect Nirav Modi, a billionaire jeweler, were arrested for allegedly conspiring to cheat the Punjab National Bank.

Modi allegedly cheated the state-run bank by using fake bank ‘letters of understanding’ to get loans. Most of the letters were sent to overseas offices of Indian banks, which made the actual loans, said Sunil Mehta, Punjab National Bank’s managing director.

Nirav runs an international jewelry empire that reaches from India to New York, with a string of high-end brands. He and his family fled India weeks before the bank registered a criminal case with the CBI on Jan. 31.

The CBI and other Indian investigative agencies searched dozens of offices and residences used by Modi and his business partners. The bank named Modi, his brother Nishal Modi, wife Ami Modi and uncle Mehul Chinubhai Choksi as suspects in its complaint.

With the Indian media reporting that Modi and his family were hiding in New York or Dubai, the External Affairs Ministry said it has suspended the passports of Modi and his uncle Choksi for four weeks.

It said in a statement that if they fail to explain within seven days why their passports should not be canceled, their travel documents will be revoked.

Meanwhile, Modi denies allegations leveled against him by Punjab National Bank (PNB), his lawyer said on Tuesday.

‘There is nothing, there is nothing in it,’ Vijay Aggarwal, a lawyer representing Modi said, referring to a police complaint filed by the state-run bank that says companies linked to the jeweler and his relatives received credit worth close to $1.8 billion between 2011 and 2017 using false guarantees supplied by two bank officials.

Aggarwal, speaking by telephone, declined to comment on Modi’s whereabouts.

‘Everything is documented,’ Aggarwal said of Modi’s dealings with PNB, adding that the bank had regularly levied fees on its dealings with the jeweler’s firms.

According to the police complaint, the two officials at a Mumbai branch of PNB fraudulently steered credit to firms linked to Modi and entities tied to jewelry retailer Gitanjali Gems , led by Modi’s uncle, Mehul Choksi.

‘They’re covering themselves up,’ Aggarwal said referring to the PNB complaint. ‘They want to avoid liability ... that is why they are cooking up this story.’

Asked about his legal strategy, Aggarwal said ‘Until there’s no chargesheet, there’s no strategy. When there’s a chargesheet, there will be a strategy.’

Choksi, who has also left the country, has not commented on the matter. Gitanjali, in a regulatory filing, denied Choksi’s involvement in the alleged fraud.

PNB did not immediately respond to the lawyer’s comments.

The alleged fraud occurred as one PNB deputy manager, with the assistance of one or more colleagues, issued over 100 fraudulent Letters of Undertaking — essentially guarantees sent to other banks so that they would provide loans to a customer.

After entering the transactions on the SWIFT messaging system, the official, who worked at the same branch from 2010 to 2017 despite normal bank practices of regular rotations - did not record them on PNB’s internal system, according to the bank’s complaint.

A PNB source said on Tuesday all its branches have now been asked to reconcile SWIFT messages with entries in their core banking system going back eight or nine years. — Agencies