7 unit apartment with no owner records

[Kevin Rogers]

I am in pursuit of purchasing a 7 unit apartment building. The area is good. The cash flow potential is very good according to the asking price. The bank needs two years of rent history to assess the value of the building. The owner has kept poor records and gave me a fumbling handwritten description of rent paid and vacancies to pass on to the bank. He has no rental agreements in writing. WOW! As I was viewing the property with the owner, he admitted that most of the tenants paid in cash (he swore he reported it to the IRS)(?). The property would be a good addition to my portfolio but I am not sure how to accurately estimate the value due to the poor record keeping by the owner. Any advice in purchasing without solid records?