Leicestershire police are investigating after around 900 cannabis plants were discovered near Coalville.
Officers were called to an industrial unit in Walker Road, Bardon Hill on Monday 22nd June in the afternoon after the owner of the building reported he could not gain access.
Police said when officers forced entry, they found hundreds of cannabis plants being grown in several different rooms.
A Leicestershire Police spokesperson added at the time officers attended the unit, no-one was present and no arrests have been made but police remained in the area.
Sergeant Ryan Ludlam said: “Our enquiries into the discovery of these plants is continuing today, and officers remain in the area while they are recovered.
“We think there are around 900 plants. The set up inside the unit was sophisticated. Tackling the production of drugs is one of our key priorities and we would like to speak to anyone who has information regarding this grow.
“We’re particularly keen to speak to anyone who visits or uses the industrial units in Walker Road, and who may have seen someone – or a group of people – acting in a manner that aroused suspicion.”

NHS cancels scheme to develop Hinckley Cottage Hospital
LCFC Appoint Gary Rowett
Lorry driver questioned after fatal crash on A46
Collapsed sewer causes delay on road Closure
Armed police respond to incident on Granville Road in Hinckley
Further delay on the A47 opening
Two Lloyds branches to close in Leicestershire
A47 Clickers Way Earl Shilton Finally Opens
