It has been my experience with IRS auditors that if you do more than 2 flips per year, they consider you a dealer.

From their I would go to the county auditor's website, get the name and mailing address of the owner and start with the handwriting yellow letters.

Probate and code enforcement can be found in county auditors office/ code violation department.

In my "full time job" I am a Commercial Energy auditor.

Include a check for the exact amount, payable to the xXxX county auditor (here).

I also wanted to note, if you are purchasing the duplex at a price that is significantly below the auditor's appraised value of the property, you can file a complaint and try to get the appraised value lowered.

So the IRS can bump taxes collected by challenging REP status, which that other thread mentions is pretty easy for an auditor and a lot of work for an investor to have over whelming documentation that doesn't look "fabricated" on the spot after the fact.The point of this thread:   Last month a CPA gave a talk to our REIA and mentioned that claiming REP also increases your IRS scrutiny of whether you 1099 your contractors faithfully. 

I am a recent graduate of Villanova University and currently work as an auditor.

Some auditors may be worse than others.Depending upon your AGI, you may not have tax due anyway if you are in the 15% tax bracket.

And along with receipts, most auditors like proof of payment such as a bank statement or cancelled check.