Police are re-appealing for witnesses following the theft of a large quantity of industrial magnets from Heygates Flour Mill in Bugbrooke.
Northamptonshire Police have released CCTV images of three men they would like to speak to in connection with the offence.
Officers believe the three men drove to and from the site in an old white van, possibly a Peugeot Expert or a Citroen Dispatch.
Anybody who saw anything suspicious in the area on Monday, 9 June at about 10.30pm when the offence took place should contact police. The magnets would have been heavy to lift and officers would also like to hear from anybody who thinks they may have seen them being unloaded at another destination.
Anyone with any information is asked to contact Northamptonshire Police on 101. Alternatively, information can be given anonymously to Crimestoppers on 0800 555 111.