From: Rabbi Moshe Sofer
To: Unknown recipient
A get messenger suspected of relations with the woman he divorced sought to marry her; the Chasam Sofer ruled she is forbidden to him on three independent grounds: the prohibition on a b'fanai nichtav messenger marrying the divorcée (even with a harsha'ah, following the Rivash), the non-credibility of his retraction of his admission, and the rumor of forbidden relations confirmed by subsequent events. The get itself remains valid for permitting her to marry others, provided the harsha'ah was properly verified at delivery.
Source: Shu"t Chasam Sofer EH II §52