What should I do ?
I have actually seen this come up a few times with clients and potential clients. If he calls the cops, they are most likely not going to arrest you here. They will probably tell him the custody of the dog is in dispute so he should hire an attorney as this is a civil matter. Based on the facts as you described them, he bought the dog for you as a gift, thus the dog was his when first purchased. Under gift law, once he gave the dog to you, it now belongs to you. Based on the information you have provided here, you are under no obligation to return the dog that was gifted to you. If he is harassing you, you should consider speaking with an attorney and filing for an Order of Protection if necessary. Good luck.