Four months ago, I sold and close a condo owned by Fannie Mae-the buyer called me asking if she has ground to file a complaint against the selleer- who made her sign a disclaimer property sold "as is"

According to the buyer, she discovered the house was burnt and was rebuilt and put in the market, but she is now found out the floors was covered up by new carpets was all burnt wood underneth.  She first suspected it when after a month she start seeing black soot coming out of the carpets, probably sucked up by vacuum cleaner and now the buyer smell burnt in the closets and in the kitchen. 

They decided to look under the carpets and discovered the burnt wood- all black and damaged was covered by new carpeting.

Is there any grounds of filing a misrepresentation or fraud in this situatuon?

Please advise.