Possible Eviction Waiting

[Andrew Eshbaugh]

Hello BP!
I've finally purchased (waiting for COE tomorrow) my first rental. It's a single family home I picked up at auction from a previous foreclosure.

The Sheriff's sale was last May and I assume there was a 6 month redemption period which past. I bought the house at auction in December '17. Now that we're ready to close escrow, I find out that the person living there refuses to sign an affidavit of vacancy and claims he knows his rights. Now I'm forced to evict or come up with another creative solution. Has anyone ever seen this before? Could anyone provide any tips/tricks?

Thanks in advance!