South Yorkshire Police warned today that a man, woman and child called at a house in Brow Crescent, Halfway, asking if the occupant wanted any gardening work carried out.
While the man was talking to the owner of the house, the woman and child asked if they could use the bathroom.
When the trio left it was discovered that a bedroom had been searched.
It is not known if anything was stolen during the incident between 4pm and 5pm on Wednesday.
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Crime Reduction Officer Dene Tinker, of South Yorkshire Police, said: "It is a sad fact of life that some criminals will impersonate others to carry out despicable crimes, preying on vulnerable people throughout the community.
"Unfortunately, this type of crime does occur with bogus callers varying in appearance and using a number of excuses to try to trick their way into people’s homes.
"The aim of the bogus caller is to try and talk their way into your home. Working in pairs one will distract you and the other steal from you.
"It is important that people are not taken in by this type of scam, often they are very convincing saying that they are from the Waterboard Board or other utility company.
"Bogus callers usually target elderly victims who live by themselves and I'd urge everyone to remain vigilant and help reduce the chance that the people you care about and your elderly neighbours are not subject to this type of crime.
“Do not buy, sell or sign up to any work on the doorstep. Do not agree to let them do your gardening or carry out any other jobs around your home."
Anyone with information should call South Yorkshire Police on 101.