I explained that the new roommate would have to apply ($30) as we needed to do a criminal background check.  

Saw the documents in the house that this person is a criminal, has been in Jail in Louisiana and has been doing illegal business and sale stolen cars. 

Be sure to look at past evictions, credit, and criminal for every applicant.  

That's an excellent question that you need a local real estate lawyer (not a divorce lawyer, not a criminal defense lawyer, a real estate lawyer) to answer after they have reviewed the contract.

In America, small business is being increasingly looked upon as a criminal behavior by both the public and governments and our society is extremely litigious. 

We just did the research on these new HUD guidelines the other day and here's a snippet of the larger article:What HUD’s new Guidance means for housing providers:Arrests records are not a valid reason to deny a rental applicant housing.Convicted criminals may be denied housing if the reason for their convictions clearly demonstrates that the safety of your residents and/or property are at risk.Blanket terms in your screening criteria that say “Any criminal convictions will be denied” are now considered discriminatory and in violation of the Fair Housing Act.The new Guidance does not make criminals a protected class, but rather establishes requirements to clearly prove why you are denying an applicant based on a criminal conviction.Remember that a housing provider violates the Fair Housing Act when the provider’s policy or practice has an unjustified discriminatory effect, even when the provider had no intent to discriminate.source and full article

But you are still gambling on the criminal aspect if you can't find a resource from their country.

As a landlord you are able to obtain credit reports, nationwide criminal, nationwide eviction, along with a bunch of other reports (sex offender, county level criminal, etc).  

There are situations in which the protection can be removed (criminal or statutory misconduct).

Specifically to their latest guidance on denying applicants with a criminal history...I will be running the background check last as part of the application process instead of in tandem - which should let all the other key criteria be met in advance.