Cannabis factories are liked to organised crime and much of the violence in Sheffield, according to South Yorkshire Police.
The claim came following the discovery of a drug den in Tinsley, in which cannabis plants worth £250,000 were found growing in a terraced property.
Earlier today, a police warning was issued around the dangers of tampering with electrics to bypass meters following the discovery of the cannabis factory.
CRIME: Police issue safety warning after discovery of drug den in Sheffield
Now, officers have revealed that the drug dens are associated with organised crime and much of the violence in the city.
A spokesman for the Sheffield South East neighbourhood policing team said: "Approximately £250,000 of cannabis that won't be making its way onto the streets was seized in Tinsley yesterday by the Darnall team and Manor team working together.
"Enquiries are continuing into those responsible.
"Set-ups like this are a major fire hazard and linked to the organised crime that causes so much violence in our city."
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.