Investigations are continuing after two cannabis growing sites were discovered in Norwich.
Police carried out warrants at two commercial properties in Norwich on August 23 this year.
The first was at a property in King Street, where 300 cannabis plants were seized, and the second was at a property in Rose Lane where 160 cannabis plants were seized.
No one was found at either address at the time the warrants were executed.
A Norfolk Police spokesman said enquiries were "ongoing".
Officers are keen to hear from anyone who may have information concerning suspicious activity around either of the properties involved.
Anyone with information should contact PC Laura Hammerton on 101 quoting crime reference 36/64921/22.
Alternatively, people with information should call Crimestoppers, an independent charity, anonymously on 0800 555 111.
Members of the public have been urged to police on 101 if they become aware of potential cannabis factories operating in their area.
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