Paying Someone Outside of Closing - Cost Basis Question

[John C.]

Hello everyone,

I'd like your opinions on this one, accountant or non-accountant.

I am about to purchase a stalled construction site. The seller, let's call him Bob, previously received a $100,000 loan from his friend, Sally, in the form of a check from her home equity line of credit to help pay for renovations. These loan checks were written directly to Bob's personal name, and in the memo was the address of the property. The loan was never recorded on the property and is a private loan. 

Now I'm about to purchase this property. At closing, the seller, Bob, wants me to write a $100,000 check to Sally to pay off her home equity (She has proof of the $100,000 check she previously wrote to Bob). This $100,000 will not show up on the closing statement since it is an unrecorded lien. If I write a $100,000 check to Sally, will this be applied to my cost basis for the purchase of the property?