Do you trust tax returns? - need advice

[David J.]

Working on buying a 20 unit apartment building. I thought all the numbers made sense on my detailed pro-forma estimates. It was hard to lose with this thing. A cash flow beast! ... then I see last 4 years of owner tax returns. Break even or lost on all 4 years 

Do I cancel the deal or do I assume he's a tax cheat and the deal is much better than it looks based on tax history?

Thank you :)