The Canada Revenue Agency is on a "witch hunt" to find whistleblowers who may have spoken to the media and exposed how it has been repeatedly duped into paying out millions in bogus refunds to scammers, according to sources.

"The consensus is that management is nervous," one source said. "Any media contacts [they're saying]: 'Don't talk to them at all, don't talk to journalists.' I think they're very much trying to control the narrative."

According to multiple sources, the CRA's senior leadership is anxious, looking for ways to silence employees and to limit media coverage.

Last month, an investigation by CBC's The Fifth Estate and Radio-Canada revealed the tax collector has been keeping Canadians largely in the dark about how many hundreds of millions of dollars in public funds it has wrongly paid out, as well as the extent to which taxpayers have had their CRA accounts hacked by fraudsters.