In the novel One, Two, Buckle My Shoe, Howard Raikes is the boyfriend of Jane Olivera. He had an appointment at the dental practice of 58 Queen Charlotte Street with Mr Reilly on the day of the murder of Henry Morley. Poirot, who had an appointment at about the same time, saw him in the waiting room but he left the place without waiting for his turn with the dentist. As he was at the location around the time Morley is believed to have been killed, and because he had behaved in an unusual manner, he became a plausible suspect.
Jane Olivera later explains the event to Poirot. Raikes had very strong socialist views. "Wilder than the rest of his crowd." He hates the kind of class and privileged background she and her family in the person of Alistair Blunt represented. At the same time she adores her uncle Alistair. She got Raikes to make the dental appointment to coincide with Blunts, hoping that Raikes would meet him. She thought if he saw what a nice unassuming man Blunt is, Raikes might change his mind. In the event, as Poirot observed, they did meet, but seemed to ignore each other. At the same time, on hearing that Henry Morley had been killed and that Blunt might have been a possible target, Jane tells Poirot that she is frightened because sometimes Raikes gets carried away. Jane agrees with Poirot's observation that Raikes is a dangerous and at the same time attractive young man.
Certainly when Poirot met him at the dentist's waiting room, he observed that Raikes is an "unpleasant and dangerous" person, "not impossibly a murderer". He looked "far more like a murderer than any of the murderers" he had arrested in his career. When Poirot meets Raikes again at the Holborn Palace hotel, these observations are reinforced. He sums Raikes up as "a wolf with ideas". Raikes has "a lean hungry face, an aggressive jaw, the eyes of a fanatic."
Nonetheless Raikes ends up saving Blunt's life towards the end of the book. He explains to Poirot that it is an odd feeling. He confesses that he was a witness at an earlier shooting attempt at Downing Street where he had tried to help a would-be assassin Ram Lal get away. However at Blunt's house the feeling was somehow different. He thinks Blunt is the kind of person who ought to be shot "for the sake of Progress and Humanity", yet when he saw someone take a shot at him, he just could not help jumping in and trying to save him. "That shows you how illogical the human animal is." Poirot tells him this shows the wide gap between theory and practice.
Raikes asks Jane to marry him, and tells her that they should get married at once, without letting anyone know, as that is the only way she will ever do it.