I have sold an investment property (house) within a few months of buying (same year) as an installment sale. I've reported the sale, including the down payment (principal) and interest received.

This property has an underlying mortgage on which I PAID interest, which offsets some of my reported interest income. Where do I report this interest expense?

I've check all over Turbo Lax and the IRS site. Just haven't stumbled on the answer yet.

Thanks in advance for any assistance.