North Wales Police is urging drivers to remain alert to the risk of catalytic converter thefts.
The devices are commonly fitted to vehicle exhausts to reduce the amount of dangerous gases emitted.
They are often targeted by thieves as they contain valuable metals and can be removed in less than a minute.
Detective Chief Insp Alun Oldfield said: "As a Force, we are still seeing too many reported thefts of catalytic converters.
"Precious metals such as rhodium, platinum and palladium are used in catalytic converters.
"The price of these metals has risen sharply in recent years and has led to an increase in the theft of catalytic converters by organised crime networks.
“January has already seen a surge in the price of Rhodium, which is likely to fuel certain organised crime networks to commit more offences.
“Hybrid cars are often commonly targeted by thieves, as their catalytic converters can contain more precious metals.
“Although some vehicle models are more likely to be targeted by thieves, we would emphasise that all vehicles equipped with these devices are at risk.”
This useful guide explains the signs of a catalytic converter theft, the actions you should take if you witness a theft, and how you can protect your own vehicle from thieves.
Spotting the signs
Thieves slide under the vehicle, often using a car jack, and use cutting tools to remove the catalytic converter.
What to do if you witness a catalytic converter theft
If the crime is in progress, call 999. People are often unsure if what they are witnessing is a catalytic converter theft, but police would rather hear about it and decide if a theft is occurring.
Do not approach suspects but, if it is safe to do so, take note of them or the number plate of their car.
If the crime has already happened then you can report it to us online or at your local police station
How can I protect my vehicle from this type of theft?
Drivers can forensically mark their catalytic converters and register their converter to make it harder for thieves to dispose of the devices.
Registering on the national database helps police identify whether recovered catalytic converters are stolen, thereby increasing the risk of detection to thieves.
Ask your car dealership for advice on locks or guards that are approved by the vehicle manufacturer and tested to Sold Secure Gold standards.
Try to ensure your vehicle is parked in a garage overnight or, if you have a commercial vehicle, park it in a secure compound.
Alternatively, park your car in a way that makes it difficult for thieves to access the undercarriage.
We advise parking close to a wall or fence and somewhere well-lit and overlooked, amongst as many cars as possible.
Vehicles that sit high above the road are particularly vulnerable.