Recent raids in India to scoop up Canada Revenue Agency tax scammers netted dozens of arrests, but the RCMP is acknowledging the phone calls are certain to continue — and likely grow in number.

What began as large call centres making and taking hundreds of calls has shifted to smaller operations to avoid scrutiny and prosecution.

"They're transferring over to a position where they have a dozen or 15 people," Supt. Peter Payne, the RCMP's top official on financial crime, told reporters Wednesday in Ottawa.

U.S.-led operations two years ago identified Canadian residents who acted as financial middlemen, perhaps also providing lead lists of Canadians to target.

The Mounties' current push against Indian scammers, dubbed Operation Octavia, is in its early stages, but Payne said "there very well could be Canadians involved in this fraud. It's something we're looking at."

The fraud scheme typically starts with an automated message that threatens to have the recipient arrested for unpaid taxes. If the person calls back, they are further threatened by someone claiming to be an agent of Canada Revenue Agency.

Scam losses continue to mount

In spite of public awareness campaigns, the number of Canadian victims continues to grow. Since 2014, the Canadian Anti-Fraud Centre has received more than 74,000 complaints, including from at least 4,000 individuals who have collectively handed over $15 million.

But the true amount and the number of victims are likely substantially higher. The CAFC said typically fewer than five per cent of victims report.

The recent raids were triggered through a visit by Canadian police to Noida, a suburb of New Delhi, following a CBC Marketplace investigation that revealed how and where many of the scammers were operating.

RCMP carry out raids on suspected CRA phone scam operations in India:

Following a CBC Marketplace investigation into CRA phone scams, the RCMP says it put greater pressure on Indian authorities where the scammers were found. 3:18

India's Central Bureau of Investigations is now working with a RCMP liaison officer permanently based in India's capital so that legal action can be taken in India to stop the actions at the source. Those already arrested are facing a series of fraud related charges.

CRA pushes message of awareness

The Canada Revenue Agency does contact taxpayers by phone. Increasingly, however, many Canadians believe the legitimate operators are actually fraudsters.

So, to raise awareness, Tammy Branch, the agency's director general of collections, said the government "will never call and use aggressive language or threaten you with arrest, and never demand immediate payment by Interac e-transfer, Bitcoin or gift card."

But that message still isn't being heard by some Canadians — primarily the elderly and immigrants, the people who fall victim to the scam most often.

While warnings exist on the CRA and RCMP websites, the federal force said it is considering providing translated versions of the information in other languages.

It will also discuss the matter with banks. Currently, there is no bank policy or regulation that would require a branch teller to ask a customer whether a large cash withdrawal is for a tax payment — or to warn customers about the scam. Some tellers do, though it is not a requirement.

More raids coming

In the meantime, the RCMP continues to work with Indian authorities with plans to conduct more raids. But the very recent proliferation of illegitimate call centres across India has compounded the problem. The investigations are complex in large part because they cross national boundaries.

The scammers use Canadian phone numbers to make it appear they are legitimate. When one is identified, the Canadian Anti-Fraud Centre works to have it shut down.

But the scammers are savvy and tend to change the number within 12 hours. Some of those phone numbers are believed to be sourced from Canadian providers, using VOIP (voice over internet protocol) technology.

Nevertheless, the RCMP said more raids are coming in India.

"We will continue to pursue those who defraud Canadians of their hard earned money," said Payne. "We are doing what we can to dismantle and disrupt these call centres."

Watch the Marketplace investigation: