Catalytic converter thieves stole devices from 20 vans after targeting a business in Wellingborough.
The business on the Finedon Road Industrial Estate was broken into some time between 5pm on October 23 and 11am on October 26.
After cutting through a fence, the thieves stole 20 catalytic converters – devices from the vehicles’ exhaust systems which are taken because of the precious metals they contain.
An attempt at a break-in was also made at the same company, which did not want to be named, on October 31 at but nothing was taken.
Chief Insp Tom Thompson, who leads Northamptonshire Police’s campaign to prevent catalytic converter thefts, said: “We know thefts like this have a terrible impact on businesses, both financially and in the disturbance caused while vehicles are off the road awaiting repair.
“That is why we have actively targeted gangs who travel around the country stealing catalytic converters and sent out the message that they are not welcome in Northamptonshire.
“I would urge anyone who knows anything about this incident, or the people who committed it, to contact us.”
In 2014, there were 133 catalytic converter thefts reported across Northamptonshire – the lowest figure since 2010.
Witnesses to the theft in Wellingborough, or anyone who knows anything about it, can call police on 101 or Crimestoppers anonymously on 0800 555111.
For more information on how to prevent catalytic converter thefts, visit the police website.