How can I sue someone living outside the U.S. that bought my business in Florida?

Your property is in Florida. Therefore, under U.S. law, you can sue in Florida. That means the business is domiciled in Florida and by law you prosecute your case in Florida. Since the brother has power of attorney, if it is unlimited, you can prosecute him too. So just be sure to name everyone in any legal action, the company, the broker, her brother as holder of the power of attorney, and even possibly successors and igns depending on how your contract reads. You really must have an attorney who is familiar with International Law. Also, since the property is in Florida, and because the default is international, you can file in Federal Court. I would seize the property! I would also ensure that the person who bought the property is of legal stauts to contract. If he is not, then you can declare the contract null and void and seize the property. But you still have to go through the legal process to do this. Also, if you can find a way to prove that the corporation "defrauded" you, you can also have the contract declared null and void. Check the terms of your contract (and I do hope you had an attorney with contract experience draw it up for you and review it). Was the deed registered? Were any payments made at all? If the brother has power of attorney then, you need to sue the company, the individual and the brother acting as power of attorney and any other parties involved for breach of contract and default. Go immediately and register a lien on the property to ensure that it can't be transferred to anyone and that a clear deed can't be issued. Get a good lawyer and study. All is not lost. You just have to learn the rules and how to "play" the games. Next time, be careful about doing business with foreign nationals. You need to learn what your rights are and how to "collect" if they default.