When the phone call begins, the man identifies himself as an investigative officer with Revenue Canada and he even gives his supposed identification number.

"The Revenue Canada is filing a criminal lawsuit against your name regarding your tax return," he told CBC reporter Pat Martel.

The problem is the man doesn't work for Revenue Canada. In fact, the proper name is the Canada Revenue Agency (CRA) and it hasn't been called the former since 1999.

Canadians across the country are hearing more and more from scammers pretending to work for the federal tax agency.

The phone calls often threaten imminent arrest and detention because, the scammers say, the recipient owes CRA back taxes.

"We would never use that type of language. I can assure you that our staff are tactful, polite and professional and we would never ask claimants to either divulge any personal information or sacrifice their financial data, or even face jail time. We would never do that," Desmond Arsenault, a CRA spokesperson who works at the tax centre in Summerside, told CBC's Island Morning.

He says the agency is working to inform Canadians about the scam, which can come by phone or email.

CRA is uploading transcripts of calls the scammers make and copies of the emails to its website, so people know what the pitches are like.

Red flags

On the main page of CRA's website, there's a link talking about the scam.

Arsenault says there are usually red flags with the calls. For example, they may refer to CRA as Revenue Canada.

In the call with Martel, the scammer said Martel was stealing taxes from the U.S. reserve, but then denied making reference to the U.S.

What should people do if they get these calls?

"When you're in doubt, I would simply hang up and contact the Canada Revenue Agency."

Its toll-free number is 1-800-959-8281.

As well, people should contact the RCMP and Canadian Anti-Fraud Centre if they feel they have been scammed, says Arsenault.

He says if someone was behind on their taxes, CRA would first send them a letter.

"We would never do surprise calls," he said.