Police are warning shop owners and consumers about two fraudulent transactions showing up in Calgary.

Officers say one scam involves someone using stolen credit cards to buy preloaded credit cards.

The stolen card won't work when it's swiped so the merchant will ask the purchaser instead to sign for the transaction, only to find out later it's a stolen card.

Police also want consumers who are buying used vehicles to pay careful attention to the VIN number inside the vehicle and to be cautious if it appears it has been tampered with.

A growing number of stolen vehicles are making their way to Alberta.