Bogus workmen have been operating in the Knottingley and Normanton area, targeting elderly people.
The reports to police suggested the con men have been knocking on doors and asking to look in the resident’s loft, claiming they are investigating a leak next door and need to take pictures of the attic area.
They have then gone into the bedrooms of the properties and look for cash or valuables, such as jewellery.
People are being urged not to allow cold callers into their homes.
Anyone with information is asked to call police on 101.