The loan purpose stated on the app was refinance home. The loan was from another lender. I asked the loan officer about the other loan and he thinks it may have be for the construction of the home, but is unsure if the loan was construction only or perm. Now the customers have refinanced the loan with us.

Would this be a refinance? or do I need to find out if the original loan was construction only and if it was, report it as home purchase?

How deep do I dig? or should I just use the stated purpose since I don't have any documentation to the contrary?

I'd want to know what kind of loan you were refinancing and if a construction only loan, it should be reported as a purchase.