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."
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Tuesday's weather for the west of the region
Tuesday's weather for the east of the region
Causes are thought to be climate change, fisheries, disease, and pollution.