I agree with @Seth Williams   Retain a lawyer to review the case, send a demand letter, and potentially defend yourself from a lien. 

General BP advice:  When you post these questions , you get a variety of responses , some just come here to bash you ,some to defend their profession ,  some want to help you , but they are too biased to provide a quality answer and finally some who genuinely have the intention to help you and provide practical suggestions ( they might be right or wrong but they have the best intention )Some don't realise the impact that they will have on a newbie - when they call you tire kicker , time waster , unreasonable ...

If your letter is worded wrong it will be recieved as an offer to buy and you could be stuck with defending yourself in a lawsuit, if nothing else.This is not to say that it cant be done well and also be very profitable to someone.

What good is a Warranty Deed if the seller can't/won't defend/cure it later anyway? 

Can you imagine working for a company that has a little more than 500 employees and has the following statistics:*29 have been accused of spousal abuse *7 have been arrested for fraud *19 have been accused of writing bad checks *117 have directly or indirectly bankrupted at leased 2 businesses *3 have done time for assault *71 cannot get a credit card due to bad credit *14 have been arrested on drug-related charges *8 have been arrested for shoplifting *21 are currently defendants in lawsuits *84 have been arrested for drunk driving in the last yearCan you guess which organization this is?

I'm not defending gurus and masterminds as yes they all are selling something.

I think you'd have a tough time proving/defending that claim in court if the tenant challenged it since the damage is below the surface of the floor, combined with the lack of any "before" photos showing the condition before the tenant moved in. 

He added me as a co-defendent to his suit after I bought the house at auction. 

Crawl thru and hide in electrical outlets, under the outlet plates and in just about any electronic device known to man, not just furniture, and clothing.Usually hard for landlord to defend in court why your not treating for pests.

If you are buying first mortgage lien then and it was recorded before city lien and other lien then there is a chance you can wipe it out in a foreclosure if you name both lien holders as a defendant.