Five men have been arrested on suspicion of killing wildlife and cats with hunting dogs in a major operation between the police and RSPCA.
Fifty police and 19 RSPCA officers took part in the raids in Firthmoor, Darlington, which saw four 18-year-olds and a man aged 19 being held on suspicion of animal cruelty.
The operation followed reports from the public that dogs were being used to hunt cats and wildlife in the Darlington area.
Six lurchers and two labradors were seized, along with mobile phones, computers and hunting paraphernalia.
Durham Police deputy chief constable Michael Banks said: "The force is committed to protecting its rural communities and tackling rural crime.
"Animal welfare is an issue at the heart of those communities and we hope that this morning's raids reassure people that activities involving animal cruelty will not be tolerated."
RSPCA chief inspector Mark Gent said: "Where we have evidence that offences have taken place, we will take action to bring the individuals involved before a court.
"I hope this sends a message to anyone involved in this kind of deliberate, abhorrent cruelty - we are actively seeking you and the next knock on the door could be us."
The men were being questioned at Darlington police station.
One of the 18-year-olds was also arrested on suspicion of cultivating cannabis and plants were seized from his home.