Mumbai: Indian police held talks with the FBI on Friday as they said they believed the kingpin of a multi-million-dollar tax scam that duped thousands of US citizens had fled the country.

A Federal Bureau of Investigation official met police in Mumbai a week after several raids on the outskirts of India’s financial capital blew the lid off the elaborate racket.

“An FBI representative visited the Thane police commissioner’s office on Friday morning and exchanged notes about the call centre scam,” Sukhada Narkar, a spokesperson for police in the Thane suburb of Mumbai told AFP.

Parag Manere, the force’s deputy commissioner, said police were “cooperating with the FBI to nab prime suspects”.

More than 770 employees were rounded up from three fictional call-centres in last week’s raids following a police tip-off.

Seventy-two were arrested and are suspected of defrauding Americans by posing as tax officials from United States’ Internal Revenue System (IRS).

They would telephone victims, accuse them of failing to pay taxes and threaten them with jail if they didn’t cough up immediately, it is alleged.

Police say the scam was operating for over a year and that the fraudsters were making around 10 million rupees ($150,000) a day.

Officers are still tracing the alleged ringleader of the scam — Sagar Thakkar, a 23-year-old from Ahmedabad in the western state of Gujarat. Police believe Thakkar, known as “Shaggy” had fled India fearing arrest.

“We have evidence that Shaggy has left India after receiving a tip-off about the raid. We are collecting evidence to track him down,” said Narkar.

India became the call centre capital of the world in the early noughties.

US and other foreign firms, drawn by India’s large, educated and cheaper English-speaking workforce farmed out a wide range of jobs from answering bank client calls and answering train timetable inquiries to IT support.

But India recently lost its crown to the Philippines and is struggling to maintain its share of the global outsourcing market.