Gold jewellery with strong sentimental value has been stolen from a house in Wellingborough.
The house, in White Delves, was broken into at about 11pm on Friday, May 29.
A bedroom window was forced open by the thieves who then searched the property.
Officers investigating the case would like to speak to a man who knocked at the door at about 10.30pm and asked if the residents had a BMW for sale, as he may be able to help with the case.
Witnesses, or anyone who knows anything about this incident, can call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.