A window blind that was "moving aggressively" despite there being no wind led police to discover a cannabis farm in a house.
The blind was in the only window in the property on Sundale Avenue, Prescot, not to have been boarded up and was seen to be moving despite the lack of air movement on Monday, Merseyside Police said.
Officers found about 200 cannabis plants in four rooms, along with electric fans and growing equipment.
A 26-year-old man has been arrested in connection with the incident and remains in custody.
'Fire and flooding'
Merseyside Police said he was arrested on suspicion of cultivating cannabis, abstracting electricity, acquiring, using or possessing criminal property and the theft of a motor vehicle.
Scottish Power was called out to make the electrics safe after the meter was found to have been tampered with and the premises were made safe by police.
Insp Brian Loughran said: "The dangers posed by cannabis farms and extracting electricity illegally in this manner pose a serious dangerous risk of fire and flooding to residents living nearby which puts lives at risk, especially when criminals tinker with the wiring and overload plugs.
"It is vital that we find cannabis farms as quickly as possible."
