Buying a $4k property in Philadelphia with Back Taxes

[Barshay Graves]

I'm going to look at a potential pick-up today. The details are $4k purchase price. However, I have done research and there are taxes due of $16,000. 

The area is rough but there is a commercial property downstairs and a residential unit upstairs. 

But regardless of everything I just mentioned I can make all my money back (after rehab) within 3 years. 

Any advice, thoughts, precautions!?