Alexander Bonarparte Cust is the triangonist of Agatha Christie's 1936 Hercule Poirot novel, The A.B.C. Murder, and all of its adaptations.

Cust started as a red herring of this novel's culprit, appearing in specific chapters not narrated by Hastings, up until he crossed his path Poirot and Hastings in the final chapters.

He was originally speculated as the ABC Killer because of his presence in all of the crime scenes, as well as his full name, but it was revealed that he was an innocent man who was actually manipulated and framed by the real killer.

He was portrayed by Donald Sumpter in Agatha Christie's Poirot, and by Eamon Farren in 2018 BBC adaptation.


Alexander Bonaparte Cust is a travelling salesman with a pompous name. He sells stockings and is epileptic. He fought in the war, and received a blow on head, making him prone to blackouts and severe headaches. He is a suspect in the murders of Alice Ascher, Betty Barnard, Carmichael Clarke and George Earlsfield. Even though he had an alibi for the murder of Betty Barnard, the police said the alibi was fake.

Nevertheless, after some delve into the case, it was revealed that Cust was actually innocent in all of the cases above, and was merely a red herring manipulated by the culprit. He was hired by the real A.B.C. Killer under the impression of a company and went to the four crime scenes solely for business.

However, as the news of the ABC Murder began to spread, Cust began to suffer from paranoia and distress because of his illness as well as his fear of being killing people. After the first three murders, Cust arrived at Doncaster under the culprit's manipulation, with the latter killed Earlsfield randomly and put the blade inside Cust's pocket when he was unawared. Thus, Cust was framed and arrested, but Poirot managed to discover the real killer by judging through his letters, before identifying the real murderer and cleared Cust's name.

Cust was eventually released and was cured from his condition. He paid visit to Poirot and Captain Arthur Hastings to give his thanks at the end of the story.


Agatha Christie's signature.png Heroes

Main Detectives
Hercule Poirot | Jane Marple
Secondary Detectives
Parker Pyne | Mr. Quin | Tommy and Tuppence Bresford
Amateur Detectives
Colonel Johnnie Race | Superintendent Battle | Bobby Jones | Frances Derwent | Arthur Calgary | Reniseb | Charles Hayward | Mark Easterbrook

Righteous Culprits
Mary Debenham | Princess Natalia Dragomiroff | Hector MacQueen | Edward Henry Masterman | Colonel John Arbuthnot | Linda Arden | Count Andrenyi | Countess Andrenyi | Greta Ohlsson | Pierre Michel | Antonio Foscarelli | Hildegarde Schmidt | Cyrus Hardman | Edith de Haviland | Hercule Poirot
Short Stories
Madame Déroulard | Ronnie Oglander

Supporters, Victims & Others
Captain Arthur Hastings | Inspector Japp | Felicity Lemon | Ariadne Oliver | George the Butler | Superintendent Spence | Colonel Johnnie Race | Superintendent Battle | Countess Vera Rosakoff | Raymond West | Joyce Lemprière
Victims & Attempted Victims
Alexander Bonaparte Cust | Miranda Butler | Mrs. Otterbourne | Pilar Estravados | Olga Seminoff
Bella Duveen | Colonel Carbury | Dr. Constantine | Dr. Gerard | Dulcie Duveen | Ginerva Boynton | Hori | Judith Butler | Lydia Lee | Miss Bulstrode | Monsieur Bouc | Monsieur Giraud | Nadine Boynton | Rosalie Otterbourne | Sarah King | Sophia Leonides | Stephen Farr | Tim Allerton | Valerie Saintclair | Virginie Mesnard

Adaptational, Homage & Non-canonical
Benoit Blanc | Marta Carbera | Linda Drysdale

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