Can credit card fraud investigation torpedo loan application?

I’m cosigning a home equity loan for somebody with whom I co-own a house. It should have been a cakewalk, as I have unusually high credit scores and no problems. I think they ran my credit report about last Wednesday or so, and we did get a “pre-approval” (though exactly what kind of commitment this is, if any, is getting fuzzier).

Tonight I found out one of my credit cards was used to make a several thousand dollar purchase yesterday in a store hundreds of miles away - the bank’s automatic system flagged the transaction as unusual and an automated voice called to ask me if this was an approved use, and press 3 if it wasn’t - so now they’re cancelling that card and sending me a new one and starting a fraud investigation. This card was one of 3 credit cards that I have but haven’t used in years, and all their balances have been zero.

I hope that this doesn’t appear as a problem on my credit report or in any other way attract the lender’s attention. Of course, there’s no direct connection between this new loan and that credit card (for instance I didn’t use the card to pay any application or processing fees). I would guess that they will only use credit information they got last week, anyway.

I did have an identity theft problem 3 years ago involving a Visa debit card attached to my checking account, but that’s all cleared up and everybody documented that I hadn’t done anything wrong.

Anybody know if this could mess things up for us? Or any advice on how to avoid problems?