THIEVES broke into a Grappenhall home on Thursday, stealing jewellery and cash.
The raid took place between 10am and 7.45pm at a home on Menlow Close when the burglars smash a patio window before stealing the jewellery, some of which was sentimental.
DC Alex Reeves, from Warrington CID, said: "It is strongly suspected that the burglary took place during the late afternoon or early evening, when the house was in darkness.
"We would like to remind residents in Warrington, particularly in south Warrington and Grappenhall, about the importance of using lights on timers indoors when they are likely to be out.
"Recent burglaries have seen addresses which were in darkness targeted as they appear more obviously unoccupied than homes which are internally lit."
Anyone with information should call Cheshire Police on 101, quoting incident 912 of November 29.
Information can also be left anonymously, via Crimestoppers, on 0800 555 111.