A taxation and accountancy firm has warned of a fraud of over £400,000.
Its online blog says: “The individual in question owned a property which he rented out to tenants over a long period of time.
“One of the tenants changed his name by deed poll to that of the landlord and applied for new identification under the new name.
“Following this, the tenant approached an estate agent to see the property. After passing all the checks, he appointed a solicitor to complete the sale at over £400,000.
“Since the estate agent and solicitor had completed all the identification checks, the property owner has been informed that he is unlikely to get any of his money back.
“The matter is currently with the police.”
Kate Williams, of Welsh tax and accountancy firm Green and Co, said the warning had originally come from a local bank.
She said: “This is a terrifying story, and we urge any landlords to use the Property Alert service provided by HM Land Registry to notify you of any activity on the property.”
It may also be possible for the rightful owner to get the Land Registry to re-register the property to them, in which case the real loser is the unwitting purchaser.