Because just thinking that i could incur criminal charges just sounds terrifying. 

What you would have committed is mortgage fraud, which is a federal offence.

Maybe see if they have a criminal record of fraud or public disturbance or anything. 

I have no idea exactly what they did, if they showed houses or whatever, but the bottom line is: if the state issues fines, files criminal charges, or simply issues a cease a desist order that is the end of these guys M/O.

Usually taxes and credit will not disqualify a borrower unless there are multiple bankruptcy, foreclosures, or fraud/criminal activity. 

They were distant friend's of someone who had once known someone who knew the owner of the house.To make a long story short, the buyer I was working with was a young guy and not connected (if you know what I mean), and I didn't want to expose him to any possible retaliation from hardcore criminal squatters.I understood why the school district backed off.

There are larger, more comprehensive tenant screening solutions that cost more but provide much more useful information than just a FICO score or criminal / landlord registry file.

Also, if there is now number associated with the address, look up the criminal court docket.

If your criminal record data was supplied by a consumer reporting agency, then you MUST supply a written letter explaining reason for declining the applicant.

You can be sued or have criminal charges filed against you for certain violations.