A police dog injured four people, including a 13-year-old girl, after escaping from its kennel.
The girl needed hospital treatment after being bitten on her arm and leg by the German shepherd-type dog in Glossop on Thursday evening.
Two men who fought the dog off her were injured. Another man had been bitten earlier, police said.
A Derbyshire Police spokeswoman confirmed the animal belonged to a dog handler with Greater Manchester Police and had escaped from its kennel at the officer’s home. The two forces have launched a joint inquiry.