Residents are being warned to be extra vigilant following two reports of suspected burglars posing as policemen in Sutton.
Two men went to a house in Stoneyford Road, told the elderly residents they were plain-clothed officers and claimed to have arrested a man trying to break-in.
The bogus officials then demanded they were let inside so they could check that money and jewellery had not been stolen.
The residents refused to let them in, challenged the pair and when they went to call the police, they suspects ran off.
The men were both white and aged in their 20s or 30s. One was dressed in navy blue clothes and was wearing a cap while the other was wearing a light grey top.
It happened at about 9pm and follows a similar incident in West End Court when cash was stolen from a handbag belonging to an 87-year-old woman.
The pensioner had answered the door to a man claiming to be a police officer who needed to check her property.
After he left the woman discovered that money had been taken.
The suspect was white, aged in his 40s, between 6ft and 6ft 2ins tall with a bald head.
DI Richard Monk, from Sutton CID, said: “Genuine police officers will carry identification so if you are concerned about a person’s validity then ask to see it.
“If they are who they claim to be, they won’t be offended if you want to make a call to the company or organisation they purport to be from and will happily wait while you make the necessary checks.
“If you are in any doubt then don’t let them into your home and report any suspicious activity to police.”
Witnesses or anyone with information about either incident is urged to call Nottinghamshire Police on 101 or Crimestoppers anonymously on 0800 555 111.