Authorities mulling whether to file criminal charges in the Christmas Day fire that killed the three daughters of a Manhattan ad exec are facing the possibility that the devastated mom might also have to be charged.

Until now, speculation focused on the idea that if there is a criminal case, the contractor boyfriend of Madonna Badger, Michael Borcina, would be charged because he physically disposed of the ashes.

But sources told The Post that authorities believe if they filed charges against Borcina, they’ll also have to charge Badger because she would bear some responsibility.