Police are warning motorists about a recent increase in thefts where catalytic converters have been stolen from vehicles.
There have been 38 incidents reported to police in the last nine days where catalytic converters have been stolen.
While towns and villages across the county have been targeted, a large number of thefts happened in the South Northamptonshire area.
All offences have occurred during the night.
Catalytic converters are part of the exhaust system and contain a number of rare metals which can make them valuable to thieves.
Vehicle crime lead for the force, Detective Inspector Ali Farr, said: “Vehicles with a high clearance tend to be targeted by criminals as they are easier to access from underneath.
“The catalytic converters can be cut or unbolted in just minutes.
“The main types of vehicles targeted include vans, pick-up trucks and 4X4s.
“We have seen a particular increase in Mercedes-Benz Sprinter vans being targeted across the county.
“Wherever possible, motorists are advised to reverse up to walls or fixed objects when parking or ensure their vehicles are housed securely.
“We urge people to remain vigilant and call us immediately if you notice anyone acting suspiciously around a vehicle, and obtain vehicle registration details of any vehicles they might be using.”
Further advice can be found by visiting www.northants.police.uk/crimeprevention.
Witnesses to any of the incidents, or anyone with information, can call Northamptonshire Police on 101 or information can be given anonymously to Crimestoppers on 0800 555111.