Cyclists are being reminded to keep their bikes locked in garages and sheds after seven were stolen in the last two weeks in Corby.
The bicycles were left unlocked on the Kingswood, Oakley Vale, Lodge Park and Danesholme estates.
Police say bikes should be locked away and out of public view.
A police spokesman said: “Always lock your bicycle, even if you are just leaving it for a couple of minutes. Lock your bike to an immovable object and where possible use a proper bike rack.”