The RCMP are crediting a raid on a massive collection of call centres in India with a steep drop in the number of complaints from Canadians about a scam involving callers who claim to be from the Canada Revenue Agency.

The Oct. 5 raid in Thane, India led to the arrest of 70 people, including alleged ringleaders and others accused of providing equipment and setting up the fake call centres. Hundreds of other employees of the call centres were detained for questioning and police said charges are likely.

The call centres had more than 700 employees, police said, and raked in more than $150,000 a day.

The raided call centres were initially linked only to a scam in which callers claimed to be working for the Internal Revenue Service, the U.S. tax collection agency. But the scam is identical to that targeting Canadian residents, says the RCMP.

After the raid, the reports of incidents of the CRA scam calls “significantly decreased to a small fraction of what was reported for the weeks and months leading up to these arrests,” the RCMP said in a press release Friday.

But it cautioned that the drop doesn’t mean the scam has stopped.

Canadian residents have reported calls from people claiming to be from the CRA, Immigration Refugees and Citizenship Canada and a number of police agencies.

The fraudsters demand payment for non-existing outstanding debts and threaten audits, lawsuits and arrest. They demand payment through services such as Western Union or MoneyGram, email money transfers, pre-paid credit cards, and gift cards.

The scammers connect with potential victims both by phone and email. There are victims countrywide, RCMP said, including men and women of all ages and cultural backgrounds.

The Canadian Anti-Fraud Centre says it has received reports of about 37,000 calls made to Canadians demanding cash for outstanding tax or immigration fees. The centre estimates more than 1,900 victims have handed over more than $5.7 million to fraudsters posing as government officials just since January 2014. That’s an average loss of $3,000.

But the CAFC says that likely represents only 5 per cent of total losses to scammers during that time, meaning the potential fraud loss is as much as $100 million.

Many victims never report their loss to police. If you or a family member has fallen victim to this fraud, report it to your local police, as well as the Canadian Anti-Fraud Centre at 1-888-495-8501 or through this online reporting tool.

The RCMP says it is also “tracking down a number of known Canadian based collaborators” and is looking for the public’s assistance in identifying suspects living here or abroad. Anyone with information should call the RCMP at 1-855-253-7267.