A clever hack of Canada’s high-tech polymer bills has Metro Vancouver police agencies warning the public to take a second look at banknotes of all denominations.

For example, criminals are splicing $5 bills to remove the holographic strips and add them to colour-copied $100 notes, making the phony seem less suspicious.

The five is still useful if they replace the hologram strip with foil or other reflective material cut in the same shape as the original, stealthily laminated in clear packing tape. The blue part remains intact, making the banknote pass cursory inspection. Both the $5 and $100 are then slipped into circulation, each with part of a genuine bill to fool casual observers -- the scammers making $105 out of a single five and a copied hundred.

Fake $5

CTV News took one of the splice-and-tape bills to the street and most people we talked to admitted they never would’ve noticed the funny fiver because they don’t usually pay attention to small bills.

"This is what [criminals] prey upon -- people not verifying the banknote,” says Bank of Canada analyst Farid Salji. “Regardless of what denomination you get you should always check your bills. And never rely on just one security feature, always check two or more.”

Despite those security features, Vancouver police have noticed surge in the tampered currency in recent months, quietly launching a series of investigations.

"We started hearing about it at the end of 2016 and continued now into 2017,” says VPD Const. Jason Doucette. "These types of crimes are driven by greed and financial gain. There's not a lot of financial gain in doing a single five dollar bill, so I suspect that there's more to come.”

Fake $5

Cpl. Vinh Ngo, head of the B.C. RCMP’s counterfeit investigation division, says while Canada is experiencing historically low counterfeit currency numbers, they still analyze thousands of phony bills every year in this province.

"It's everywhere, really. There's no certain geographical patterns,” he told CTV News at E-Division headquarters in Surrey.

Ngo warns retailers and consumers to be extra-vigilant in evening or low-light conditions where it’s tougher to pay attention to the security features. He adds that while the splice-and-tape scheme is unsophisticated, they’re investigating broader implications including gang involvement.

“Organized crime can mean many things, but there are some elements of organized in this, in general."

Ngo is part of the RCMP’s Federal Serious and Organized Crime division, and points out tampering with currency and even knowingly circulating it are federal crimes and come with a maximum 14-year prison sentence. Failing to notice a banknote is fake doesn’t get you in trouble, but retailers, servers and everyone else who deal with cash have the right to refuse any currency they think is suspicious.

Fake $5

The Bank of Canada has tips for retailers and consumers to quickly and unobtrusively verify the authenticity of their cash at point of sale. Quick highlights include: matching faces on the main part of the note with the upper hologram strip, the upper hologram being dull while the lower portion is sharper and more colourful, and tiny transparent numbers that match the value of the bill.

If you haven’t recognized a counterfeit bill until after you’ve read this story, there’s still something you can do.

"We want you to call us, we’re not going to assume you’re a bad person,” says Doucette. “And if you don't want to come to police, go to your local bank and drop off the note. It'll get into the same system so we're able to track them and that'll assist with our investigation."

You won’t get your money back, but you can help law enforcement track down the people who are responsible and keep them from scamming anyone else.