Motorists with keyless entry cars been warned to be vigilant after 16 luxury vehicles were stolen in a spate of thefts across counties Down and Armagh.
The vehicles were all taken in the early hours of the morning but the thieves did not force entry nor did they take the keys from the owners.
Police believe they got into the cars by redirecting the wireless signal from the motorists' key fobs while the fob was still inside the owners' homes.
They listed ways to stop keyless theft.
Their suggestions include storing key fobs in a metal container or a microwave to block the wireless signal, through to more traditional methods like locking garden gates.
Keyless entry systems allow car owners to open and start their cars without handling their key.
The Police Service of Northern Ireland (PSNI) pointed to a pattern in recent thefts and said keyless car robbers were focusing on "high-value" vehicles.
Brands in the list of 16 stolen vehicles included Range Rover; Land Rover; Lexus, Nissan and BMW.
PSNI Det Insp Dan Kelly urged motorists to protect their vehicles by keeping them in a garage or locking driveway gates, where possible.
He also suggested using steering column locks or chains to prevent theft.
The officer advised that all car keys, including spare sets, should be kept away from exterior doors and walls of the home.
"Motorists can use a blocking pouch (lined with metallic material) to help block the wireless signal from your key fob," he added.
"Placing fobs in a tin or the microwave can also help block the wireless signal."
He added that vehicle tracker devices were an "excellent way to combat car thefts".
Earlier this year, it was reported that some of the UK's newest and most popular keyless entry cars were at risk of being stolen in seconds.