How can I do my due diligence on a 4 house property?

[Calvin Harrison]

I've found a property that is listed at $650,000 for 4 homes on a private drive way. The properties sit on 1.2 acres, with an additional 1.8 acres of land. I'm having a hard time finding financial history on this property. It doesn't show up on our county appraisal site. How can I find the information needed to see if this will be profitable?