In the novel The Murder of Roger Ackroyd, Doctor James Sheppard is the physician in King's Abbot and the younger brother of Caroline Sheppard. He helps Hercule Poirot investigate the murder of Roger Ackroyd. Caroline describes him as "quite an old fogey", definition which he uses himself later in the novel.
He lived next to The Larches, Poirot's temporary residence. The two meet after a fortunate coincidence, when Poirot throws a marrow that lands near Dr. Sheppard. Sheppard is at first amused and interested about Poirot, which jokingly replies to him that "throwing marrows isn't one of his hobbies, don't worry".
At first, he thinks Poirot is called "Porrott" and that he is a retired barber. Due to Hastings not being present in this novel, he takes his part of Poirot's assistant. He is the one who helps Poirot to reunite all the suspects and make a meeting. Other than being Poirot's assistant, Dr Sheppard is the narrator of the novel. This is the first time that Agatha Christie uses the technique of unreliable narrator, the other being in Endless Night.
He lives with his sister and has a parlourmaid, Annie. He is also good at mechanics. He forbid his maid to enter the study room since it was full of delicate mechanisms which could be ruined. Dr Sheppard first appears after visiting King's Paddock, the house of the deceased Mrs Ferrars who had killed herself at the beginning of the story. He and his sister sit at the breakfast table where Caroline points out that she believed Mrs Ferrars had killed her husband and later committed suicide because of blackmail, or remorse. Sheppard believes it's rediculous, and the chapter leaves open whether Mrs Ferrars suicided or not.
After visiting some patients, Dr Sheppard encounters Roger Ackroyd and Miss Gannett which leaves shortly afterwards. Roger tells him that he is worried about the death of the woman he wished to marry, and invites him to Fernly Park to dine.
There he comes across all of the family members and servants of the household which he briefly describes. After a not very cheerful dinner, Roger and Sheppard talked in the study room about Mrs Ferrars. Roger tells him the same Caroline Sheppard said, confirming her hypothesis. The butler Parker gives him a letter of Mrs Ferrars in which he exposed her blackmailer, and Ackroyd asks the doctor to leave. James Sheppard leaves with Roger Ackroyd who still hasn't read the confession.
Due to Sheppard being Poirot's assistant, he witnesses several key events in the plot of the story (like Mark Easterbrook in The Pale Horse). He receives a call apparently from Parker saying that Ackroyd was dead, but Parker claims to not have called him out. Sheppard discovers the body, and finds two vital clues: a pen and a wedding ring. He accidentally reveals the detail of the ring with his sister and Miss Gannett, the "top newsmongers of King's Abbot". This started tens of hypothesis, but none of them was actually the truth.
Dr Sheppard was actually helping the prime suspect of Ackroyd's murder hiding him in a clinic near Cranchester. On the night of the murder (as stated before), he had left Ackroyd at 8:50. Upon leaving Fernly Park, he came across a mysterious man with a trace of American accent in his voice. He later helps identify the mysterious man, who is revealed to be Elizabeth Russell's illegitimate son. Poirot first exonerates Dr Sheppard from the suspect list because Ackroyd's voice was heard at 9:30, but in the last chapters he is exposed as the murderer. The voice heard was actually a dictaphone recording. Poirot suggests Doctor Sheppard to either surrender to the police or take his own life. Sheppard chooses the second option, and, in his confession, reveals that he blackmailed Mrs Ferrars and killed Roger Ackroyd to avoid being exposed. He then suicides through an overdose of Veronal. This is one of Christie's most discussed plot twists and it would still be talked about today even if she hadn't written other novels.
For more information about the crime, the timing and the clues, visit the page Roger Ackroyd.
Agatha Christie's Poirot
In the Agatha Christie's Poirot TV adaptation of the novel, he was portrayed by actor Oliver Ford Davies. He is presented as a more unpleasant character than in the original novel and here he owns a gun too. He first reminds Poirot of his appointment wih Roger Ackroyd, and he later appears in his house. Here he receives the call from an Inspector Davis who tells him that Mrs Ferrars has died. He later goes to dine at Fernly, where he has a role similar to the one in the original novel. As in the original story Parker points out a key detail (an armchair which wasn't supposed to be in that certain position) and Sheppard kills him to avoid being exposed (not present in the canonical version). He later kills himself with a gun after a chase through a factory.