Thieves have targeted four different cars in what police believe are linked crimes in the Doncaster area earlier this week.
Hundreds of pounds worth of property, including a Blackberry, sat nav and iPad, have been taken from vehicles.
None of the vehicles was damaged.
A BlackBerry phone, worth about £100, was taken from a Toyota Avensis at Boswell Road, Bessacarr, between midnight and 7.30am on Monday.
And a sat nav and iPod, totalling £150, was stolen between 6pm on Sunday and 7am on Monday from an Alfa Romeo parked at Cornflower Drive, Bessacarr.
Crooks also raided a Ford Mondeo at Thealby Gardens, Bessacarr, between 3.30pm on Sunday and 9am on Monday, but nothing was stolen.
Meanwhile a coat, sat nav and money was taken from a black Chrysler at Edencroft Drive, Edenthorpe, between 11pm on Sunday and 8.30am on Monday.
Officers believe the incidents may be linked and are reminding people not to leave valuables on show.
Meanwhile, police are also warning workers with trailers attached to vans to ensure that any property is protected. The safety message comes after a trailer containing a hydraulic pump and jack hammer, worth £700, was disconnected from a Ford transit at Vicarage Close, Hatfield, Doncaster, between 2.15pm and 2.30pm yesterday.