Residents are being urged to stay vigilant about doorstep thieves.
It comes after two incidents - half an hour apart - on 2nd January in which a woman in her 90s and a man in his 60s were targeted.
The man, who lives in the area close to Mallatratt Place, Mansfield Woodhouse, answered the door to a woman at about 1.20pm. She said she was from the council and needed to check the drains.
While they were out of sight at the rear of the property, it is believed a man entered the house and stole money and a set of car keys.
At 2pm, the elderly woman who lives in the Netherfield Lane area, Church Warsop, answered the door to two women, again claiming they needed to check the drains.
One of the callers took her to the rear of the house to discuss the drains while it is believed the other woman made her way into the house. She made off with money and a bank book.
It is believed the incidents are linked.
T/Detective Sergeant Rick Ellis, of Mansfield CID, said: “The victims of these thefts have been left distressed and shaken up. Do not let anyone into your home who you have not made a prior appointment with. Anyone who is a legitimate caller will have identification with them.
“The police are appealing for witnesses who may have had similar calls on that day to come forward.”
Anyone with any information should contact T/Detective Sergeant Rick Ellis at Mansfield CID on the non-emergency number 101 ext 3464.
Alternatively call Crimestoppers anonymously on 0800 555 111.