The original post doesn't make this sound like it's a purchase of the assets only. I think John was planning on buying the entire business or potentially becoming a partner in the business. He's looking to take over an existing store and turn a profit. The owner has mentioned the store supports itself, but doesn't currently ear a profit and John is concerned if maybe the reason the store supports itself is because the owner skirts the law here and there.

I think there is a measure of trust in this sale. John should be looking at the businesses books and making an assessment of how much he can earn from the store, but a certain amount of the information he's going to use is likely going to come from the the current owner.