In the short story The Under Dog, Captain Swann is a guest at the Golf Hotel at Abbots Cross, near Mon Repos, the residence of the Astwell family. Poirot enquired into the movements of the hotel guests in the course of his investigation into the death of Sir Reuben Astwell. According to Miss Langdon, the hotel manageress, Captain Swann had not gone out for a walk after dinner on the night of the death of Sir Reuben.
Captain Swann is not featured in the film adaptation of the story in Series 5 of ITV's Agatha Christie's Poirot.