Thieves, normally working in pairs, will target a car parked outside a house.
One criminal will hold a device close to the car that boosts the signal meant for the key, while the other thief will stand close to the house with another device that relays that signal to the key, fooling the system.
Once the cars have been broken into, they will be stripped for parts, police say.
Car manufacturers have begun introducing new technologies to prevent keyless theft, such as motion detection technology.
What Car? was unable to break into cars that had motion detection installed as a safety measure, however the technology is not available across the car market.