Six people have been arrested and 14 dogs seized during raids to combat dog fighting in Nottinghamshire, Lincolnshire and Hertfordshire.
Police and RSPCA officers seized five pit-bull dogs from two properties in Ragnall, Notts, on Wednesday.
Two injured dogs and one dead pit-bull were among eight recovered from two addresses in Grantham and Kexby, Lincs. One dog was seized in Anstey, Herts.
Four men and two women were arrested in connection with dog fighting.
They are in custody awaiting questioning.
Officers said dog fighting paraphernalia including treadmills used to improve the animals’ fitness were also recovered.
A post-mortem examination is due to be carried out on the dead animal. The remaining dogs are now in RSPCA care.
Ch Insp Mike Butcher, of the RSPCA Special Operations Unit, said: “People may think that dog fighting has gone away but that’s simply not true.
“We would ask people to continue being vigilant and call us if they suspect that dog fighting, badger baiting or cock-fighting are taking place.
“These so-called ‘sports’ belong in the dark ages, so hopefully we can eradicate them from the UK.”
The raids were part of the RSPCA’s Operation Cannon.