Not to steal Bill's thunder Julian but to address your question we have to pause on the idea that you implied of "perfectly good".  

I found a property that should be a steal, but the seller has a tenanat who stopped paying rent the previous month.

Lots of things went wrong, including the main guy in the underlying deal stealing some of the money.  

For instance, assuming you have 2 identical properties (hypothetically, but I have seen this quite often in new subdivisions where owners build the same model but some add a basement) one with basement and the other without basement.Property without basement:  3,000 square feet selling for $300K, or $100 per square foot.Property with basement:  identical 3,000 plus 1,000 basement, for a total of 4,000 selling for $450K.  

And if someone does end up stealing it, what can I do about it?

To steal a tip or two from Dave Ramsey he says to save up an emergency fund of 1K then pay off debts start with the smallest (regardless of interest rate) and once the smallest is paid off then attack the next and so forth.

There are of course hybrid deal structures and other circumstances that make no one deal identical to the other.  

@Joshua McGinnis while you need to make sure that you have your margins, you cant try to steal a home and last at this game.

(b) If the records of a series are maintained in a manner so that the assets of the series can be reasonably identified by specific listing, category, type, quantity, or computational or allocational formula or procedure, including a percentage or share of any assets, or by any other method in which the identity of the assets can be objectively determined, the records are considered to satisfy the requirements of Section 10A-5A-11.02(b)(1).

And they are stealing your money.