A pre-planned operation was carried out today (Tuesday 20 February 2007) to investigate alleged offences committed under Section 145 of the Serious Organised Crime and Police Act 2005.
The operation involved both Humberside Police and West Yorkshire Police officers assisted by other national police agencies.
The arrests were made at a number of addresses in both the Humberside and West Yorkshire police areas.
A 56-year-old woman and a 30-year-old woman were arrested in Preston, East Yorkshire and a 17-year-old male from Leeds and a 27-year-old male from Shipley were arrested in West Yorkshire.
A large number of items were seized during extensive searches conducted throughout the operation.
All four people remain in custody whilst enquiries and searches are concluded.