Eight vehicles which were detected using illegal fuel have been seized by police.
The operation was conducted by Magherafelt Neighbourhood Policing Team and Revenue and Customs.
Seven of the vehicles were returned to the owners.
More than £4000 was paid out in fines.
A number of motoring offences were also detected - these included driving without insurance.
Teenager killed and child left in critical condition after Belfast road crash
Stormont leaders and chief constable in show of unity against station attack
Firefighters continue to battle ‘soul‑destroying’ wildfires in Mourne Mountains
Political leaders unite to condemn ‘cowardly’ attack on PSNI station