Let me know if I can help,
Best of luck
Please correct me if I'm wrong but in order to have an American passport you would have had to at one time had American citizenship.
I am a member of FIABCI/International Real Estate Federation so if I can be of any further assistance to you please feel free to contact me at email@example.com
This way they can search and even preview properties for you. When you come to look and purchase, they can guide you through the process and make sure you have all the paperwork and items you will need to buy given your status.
good luck with your purchase.