The Indian police have uncovered a chain of fake call centres in Mumbai and arrested 70 people who posed as officials of U.S. tax department and scammed thousands of Americans..

The fraudsters ran fake call centres and sent threatening voice mail messages telling the U.S. citizens that they owed tax and must respond. Those who fell prey were asked to send out thousands of dollars to "settle" their cases, the police said.

The scammers who spoke with American citizens were trained to trick the "customers" into a "nervous wreck" with their questions. If a person said, for instance, they he or she has already paid the IRS, the call centre "executive" will confidently respond with, "What we are investigating is the miscalculation seen in your tax filed which makes us assume your intention was to defraud the IRS and the income tax law."

To ensure they don’t get traced back easily, these scammers instructed victims to buy gift vouchers from various companies and share the code, the police said, adding that they got a tip-off recently about these people.

They are questioning around 600 more people who could also be part of the ring. They raided the building earlier this week and seized hundreds of hard drives, servers and other gadgets. According to the police, these scams were oddly very effective, bringing in over $150,000 a day.

According to NDTV, 70 percent of the scam’s were done from India whereas other members are believed to be working from within the United States.