If the owner is in jail, then he can be found. You may have to write. If he is nearby, you can probably even visit. If you can find his lawyer, it might be best to deal with him. You will have to demonstrate that it is in his client's best interest to sell to you. And he may not feel that it is.
In my limited experience with one seller who was incarcerated, he did not care much what happened to his property.... more