What are possible criminal consequences for real estate fraud

Criminal Defense/Lawsuits: I helped a friend acquire a property with no money down and it has renters. The renters wanting to purchase with a lease purchase agreement. I put the paper work in order, they signed, she signed. Everyone has original copies. I interview several investors and found a good one to pay cash and to purchase the note (and create a WD and etc)and pay off the balance to the lien holder. Prior to all this She asked me how much I wanted, I asked her for $5,000.00 and she said she wanted $6,000.00...and divide the rest equally, so the renters paid $4,000.00 down , which I received and she received $20,000+ from the investor.
She told the renters and signed an affidavit that she never signed the contract and she never knew about the $4,000. So now that the renters are purchasing the house from the investor and she received her monies, the renters now want their $4,000.00 or will charge me with something criminal. I don't know what to do, should I get a criminal or civil attorney?
What kind of documents have to be filed to stop the criminal? So that it will give me time to interveiw attorneys to file some kind of charge for falsifying an affidavit and embarrassment and trying to ruin my reputation.
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