
I would gather all the evidence I could showing that the dog is yours. For example, photographs of the dog, vet records, etc. Check to see if you have any of the dogs hair (maybe in a dog brush) as you may be able to have testing done to show the dog is yours. I would then contact the Sheriffs office again showing them the proof you have that the dog is yours. If they are still unwilling to get your dog, you could hire a lawyer to file a civil suit against the dog thief. Good luck! I hope you are able to get your dog back.