Three cannabis farms worth a combined £1.5 million were uncovered by officers during a number of police raids across Sunderland.
More than 3,000 cannabis plants were seized during three warrants across Hendon, Ashbrooke and Hetton-le-Hole this month after reports from residents about suspected drug supply.
The drugs have now been seized to prevent them from being sold on the street with officers thanking the community for their help.
Chief Inspector Nicola Wearing, of Northumbria Police, said: "These types of sophisticated operations often have links to serious and organised crime, with the money earned from them used to fund other criminality.
"Make no mistake; the three farms that we detected and dismantled will provide a dent in the pockets of organised criminals.
"Two of the seizures came off the back of members of the community getting in touch about suspected criminality in their area. That allowed officers to take swift and decisive action – and ultimately keep these drugs out the hands of vulnerable people in our communities.
"The other came from our partners at the fire service who attended a house fire and found the farm within.
"Quite often with these operations, the electricity has been by-passed – posing a real and significant danger to not only that property but neighbouring ones too.
"Nobody wants to live next to a potential death trap. If you suspect someone to be involved in drug supply in your area, pick up the phone and report it – by doing so, you could save lives."
An investigation is ongoing into each of the discoveries.
