Raiders smashed the window of a Cockermouth shop overnight and took a necklace from the window display.
They broke into WM Walker jewellery shop on Main Street.
A police spokesman said: "We were called at around 6.45am by a member of the public who spotted the window of a jewellers in Main Street had been broken.
"It is believed a necklace has been taken from the window display.
"Officers would like to hear from anyone who witnessed what happened or who saw anything suspicious in the area at the time."
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