A car and jewellery were stolen when a burglar broke into a house in Sheffield by forcing the back door
The crook struck in Arnold Avenue, Gleadless, last week and took a Toyota Rav 4 worth £1,500 and jewellery worth £3,000.
A police probe into the raid is underway.
A South Yorkshire Police spokesman said: "Can we please ask from a crime reduction point of view that vehicle keys are not left on display in your property when you are not at home.
"Also when in your property make sure you have sight of your car keys, don't leave them on a kitchen table with an insecure outer door, and you be in another room. Someone will seize this opportunity.
"If you leave your property and are not taking your vehicle, either take your keys with you or find a secure place within your property."
Investigations are also underway into the theft of a £20,000 Ford Transit van from Retford Road, Handsworth and another Ford Transit from Eastcroft View, Westfield, which was found in Doles Lane, Whiston, Rotherham.
Anyone with information should call South Yorkshire Police on 101.