Cannabis plants were discovered at the scene of a fire in Blackpool.
Officers are unable to say how many plants were inside the property as many were destroyed in the flames.
Police were called in to assist fire crews following the incident in Alexandra Road, South Shore on Saturday.
The fire was reported at 3.40am and crews from South Shore and Blackpool attended.
Firefighters wearing breathing apparatus entered the three-storey property and used hose reels to battle the flames.
The decision to call in police was made shortly after firefighters arrived at the scene.
A team from Electricity North West also attended and made the supply to the building safe.
A Lancashire Police spokesman said: “We were called to an address in Alexandra Road, Blackpool at around 3.50am on Saturday at the request of the fire service.
“The fire was contained by Lancashire Fire and Rescue service.
“Once officers were able to gain access a number of cannabis plants were found.
“A lot of them had been destroyed by the fire.”
Fire crews remained at the scene for around six hours.
The blaze is being treated as suspicious and police investigations are ongoing.