So, you've bought a home in a trustee's sale on the courthouse steps and you've just found out that the prior owners are not living there, but tenants of the prior owners are. What does that mean? According to the "Tenants in Foreclosure Act of 2009", that means that you have to give them 90 days' notice before filing an eviction complaint with the court. Yes, 90 days. The notice also has to have a special cover sheet entitled "Notice to Renters" which has specific language with regard to where the tenants can receive legal aid or legal help, and encouraging them to do so.
Also, if you bought the property as an investment and you don't intend to live in it yourself, and the tenant has a bona fide lease, which could have another year or more left on it, you have to honor the lease and collect the rent. You're also responsible for the security deposit if you did not obtain it from the prior owner.