Detective Inspector Louise Ludwig said: "We would urge all shoppers to be wary of anyone who might be watching you at the checkout.
"Always cover your PIN when you enter it into a cash machine or Chip & PIN machine at the tills.
"Try to avoid being distracted by people asking for directions, and keep your valuables safe."
More top news
Philippa has Sunday's weather for the east
Philippa has Sunday's weather for the west
Philippa has the latest weekend weather for the east