You can hire a lawyer to investigate and file a lawsuit to get your dog back if he/she is able to determine where the dog is.
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First of all, is your dog chipped? If so, ownership will be proven once the dog is located. You need to insist that the police follow up on the leads you provide. Speak to the watch commander, the lieutenant or the chief. Go to the local press and ask them to help you. You can hire a lawyer to helping you along. The suggestion of a lawsuit is good but you will have a hard time proving the woman has/had you dogs unless you have more facts that provided here. Best wishes on getting your dog back.
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