Our home recently flooded during the storm Allison. We have become VERY familiar with disinfectants. I would recommend a product by the name of Consan. It can be purchased at like a Lowes or Home Depot. It is in the gardening/ bug spray area of the store. The product is used for sanitizing instituitions as it also has many other uses. You will need to use a mask, gloves and a sprayer when applying the product. Read the directions carefully. It's some pretty powerful stuff. This may help in santizing and just cleaning the area after you have identified where the problem lies. Hope this helps along with the other suggestions you have received.