I have a question about finding out whether someone operates a legitimate business...?

There is a couple that is claiming to be a Limited Liability Corporation house inspection agency. They appraise and inspect foreclosed homes. I am not entirely sure that they are telling the truth about being an actual certified business. I have looked them up on the BBB website, and nothing could be found. I also looked them up on my state's Secretary of State website, and there was nothing about them or their business there, either. How would I go about finding out whether or not they are actually being truthful about their crendentials/ripping people off?