A good question to ask the previous is if they would re-lease to the tenant. The answer doesn't have to specify reasons, but does in effect tell the whole story.

I know what you saying since I have the same experience before even both the worst tenants are Section 8 tenants. Please check into http://www.ntnonline.com/. They are a national company and maintain a database about tenants' record. Please do a home visit before renting out your unit and check on the prior landlords not the current one.