Police uncovered a cannabis farm in St Helens after receiving reports from neighbours about a “strange smell”.
Officers were called to an address of Nicholson Street in Parr at about 11am on Wednesday, January 7.
Inside, they found 222 cannabis plants - at varying stages of growth.
The stash was estimated to have a potential annual yield of up to £250,000.
Three upstairs rooms, inculding two bedrooms, had been rigged up with sophisticated hydroponic equipment and the electricity was found to have been illegally bypassed.
Detectives are keen to speak to a man described as Asian, 5ft 7ins tall with dark hair and a spider tattoo on one hand.
He was last seen near the property wearing a light blue top.
Neighbourhood inspector Elaine Collins described cannabis farms like this one as “death traps”.
She said: “The growing of cannabis brings dangers to neighbouring properties. Cannabis farms are a serious fire risk. Those who set up these farms often tamper with the electricity meters to steal electricity, and there will generally be a number of hot lamps hooked to overloaded electricity sockets and an extensive watering system.
“Electricity and water are never a good combination and the fire service have seen an increase in the number of fires they have been called to as a result of fires caused by the crude systems put in place by the people who set up these farms.”
She added: “Cannabis cultivation by criminal gangs can cause serious harm in our communities. Gangs involved in the cultivation of cannabis are usually involved in other serious organised crime and they often rent residential properties such as flats or houses.
“Organised criminals see cannabis cultivation as a low-risk, high-profit venture, and use it to fund a wide range of other criminal activities.”