Mumbai police have smashed a sophisticated international vishing operation which could have netted ringleaders as much as $7.5 million from US victims who thought they were calling from the IRS.
Police have detained over 700 staff at several call centers in the Thane suburb of the city and seized hundreds of servers, hard disks, laptops and other equipment as well as documentation to help with their investigation.
They were tipped off by a disgruntled employee of one of the call centers, sources told local media.
It is believed that members of the gang based in the United States obtained contact details for the victims from the darkweb.
Staff back in Thane would then call up these targets pretending to work for the IRS and claim the victim had outstanding taxes or fines to pay. This was ordered to be paid through online pre-paid cash cards, to help muddle the money trail.
The callers also used VoIP via proxy servers, presumably to anonymize their location.
Staff are said to have been heavily coached to speak with an American accent, and handed a six-page script to use in their vishing attempts.
Police in the US are now apparently hunting members of the gang based over there, and their counterparts in India have claimed that the operation may also extend to the UK and Australia.
Vishing is nothing new, of course, with over half (58%) of Brits claiming to be affected in 2014 at a cost of nearly £24 million, according to Financial Fraud Action UK figures.
A year later it was rated the most popular type of cyber fraud tactic around, according to Get Safe Online.
However, the scale and sophistication of this latest discovery in India should be yet another reminder that police around the globe must stay vigilant to the threat.