Two people pretending to be from a company which provides carers tricked their way into an elderly woman’s house in Wellingborough.
The incident happened on Thursday, February 23, between midday and 5pm in Fourth Avenue.
It isn’t believed anything was taken but the victim’s bank statements and documents were searched and studied.
The offenders are described as white and in their twenties.
One was a man of about 5ft 8in who was wearing a brown coat and blue jeans.
He was accompanied by a woman of about 5ft 4in who was wearing a white cardigan and black trousers.
A police spokesman said: “We are urging people to be vigilant and advise people never to open the door to anyone they are not expecting.
“People are encouraged to pass this advice on to friends, relatives and neighbours, in particular those who are elderly or more vulnerable, and to remember the key advice: If you’re not sure, don’t open the door.
“Anyone who has suspicions or concerns that distraction burglars or rogue doorstep traders are operating in their neighbourhood or targeting someone they know should call 101 or the dedicated doorstep crime number on 0345 2307702.
“For Trading Standards advice, call 0845 404 0506.
“Always call 999 if you think a rogue trader is on your doorstep.”
Anyone with information can contact police on 101 or Crimestoppers anonymously on 0800 555111.