With most telemarketing scams, you can tell what it is they're after, like your credit card number or personal information.

But there's a new one that is much more subtle.

And you may not know what you got yourself into until you're in the middle of a fraud investigation.

David Ambrose doesn't like telemarketers. That's why he subscribes to the National Do Not Call List.

So when a man called stating he was from the Do Not Call List asking him if he'd participate in a program to trace illegal calls it made sense.

The man told Ambrose he would receive an automated call giving him a 5-digit number. He told Ambrose to write the number down so he could repeat it to the man when he called back to activate the trace program.

"I thought it was a bit peculiar, but I said OK because I wasn't really paying attention," says Ambrose.

The automated call came with the 5-digit number, but Ambrose noticed it wasn't from the government. It was from Craigslist, the online classified ad company.

He smelled a rat and when the man called back for the number, Ambrose refused to give it. The man became irate and Ambrose knew his instincts were correct.

"Every minute that went past, I though more and more that this is definitely not right and there's

no government employee that would be so adamant to do this," he says.

This scam was born when Craigslist implemented a new security measure to curb the number of scammers posting phony ads designed to steal people's money and personal information.

Now when you go to place an ad, you must type in an actual working phone number, something con men don't want to do. Craigslist's automated system then calls that number and provides a 5-digit pin number. You must enter that number to activate your online account and place your ad.

So now the bad guys need those pin numbers to keep posting phony ads with anonymity. And if you give them the pin, your phone number will be the only legitimate contact.

"What they're doing is hijacking your phone number for their own purposes and when those purposes turn out to be criminal, you're gonna be the one getting called," warns RCMP Sgt. Patrick Webb.

He says this new scam is easier to fall for than most, since people don't see the harm in giving out the pin number.

"And what we're finding is that if you do refuse to get them the number once you've got it, they go from very cooperative and convincing to threatening," adds Webb.

The RCMP has heard of callers posing as agents from governmental health and inspection agencies as well.

CTV contacted Craigslist several times to discuss the company's security measures and ask if the "working telephone number" requirement applies to all ads, or only ones in certain categories.

Craigslist never responded.



