Q: I was given a dog back in June 2022, now its almost 2023 and their threatening me to give the dog back?

A: If the dog was not the property of the girlfriend, she had no legal right to give it away without authorization and consent of the incarcerated owner. If the incarcerated owner gave her that consent, then that's a different matter. A person (you) who receives a gift or even purchases property from one who does not own the property (and is not the authorized agent of the owner with authority to do so), does not receive legal title to that property. I assume you knew the dog belonged to the incarcerated owner when you received it. What evidence do you have to confirm the actual owner approved of the transfer of ownershp to you? In the absence of an express agreement by the owner to transfer ownership, or authorize his girlfriend to do so, you would have to establish that the owner "abandoned" voluntarily and intentionally his ownership of the dog. Incarceration is not a voluntary act, so it is doubtful you could prevail on that theory.

As far as the vet bills and any other costs incurred, you can sue the owner for "unjust enrichment" in the amount of the bills and cost of food to care for the dog. The theory is, you expended reasonable and necessary money for the benefit of the owner of the dog to care for his dog while he was incarcerated, and he should reimburse you for those expenditures. You will need all your receipts and proof of payment. It's a Small Claims action if the amounts do not exceed $5,000.

As far as his getting the dog back from you, if you refuse, he can file a "replevin" action against you in district court, which is a civil claim where one party seeks return of property that is wrongfully held by another. You can defend that action on the theories that the dog was legally gifted to you, or that it was abandoned by the former owner; and you can counter-claim in the alternative that he owes you the vet and food bills. Then a judge will decide the case.