# Arthur Sinclair — The Wrong Letter character guide > Arthur Sinclair in The Wrong Letter by Walter S. Masterman. **Role:** major **Also known as:** Superintendent Sinclair, Even Sinclair, Sinclair, Mr. Sinclair **First appearance:** 0001-the-wrong-letter ## Snapshot A Scotland Yard superintendent of the unglamorous, real-life sort — trained, unpretentious, and quietly grateful for a friend with sharper instincts than his own. ## Who they are Sinclair earned his post through solid work in India and makes no claims to brilliance, which is precisely why he values Collins's help and tolerates his riddles. When a woman's voice coolly informs him the Home Secretary has been murdered — and signs off as the murderer — he is staggered but not shaken, and sets the machinery of official inquiry in motion. His steady, procedural mind becomes the counterweight to Collins's leaps, and the reader's anchor as the case turns strange. ## Relationships ### [Sylvester Collins](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/sylvester_collins) _rivalry_ Arthur and Sylvester are locked in a bitter rivalry, likely over Mabel or professional standing. ### [F. D. Boyce](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/f_d_boyce) _professional_ Arthur and Boyce are colleagues or partners in some enterprise, working together against Sylvester. ### [Mabel Watson](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/mabel_watson) _romantic_ Arthur is a suitor or former lover of Mabel, creating a love triangle with Sylvester. ### [Lewis](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/lewis) _professional_ Lewis is Arthur's assistant or servant, carrying out his orders. ### [Mr. Allery](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/mr_allery) _professional_ Arthur and Mr. Allery interact in a business or legal context, often with tension. ### [Sylvester Collins](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/sylvester_collins) _rivalry_ Arthur and Sylvester are locked in a bitter rivalry, likely over Mabel or professional standing. ### [Mabel Watson](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/mabel_watson) _romantic_ Arthur is a suitor or former lover of Mabel, creating a love triangle with Sylvester. ### [Sylvester Collins](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/sylvester_collins) _rivalry_ Arthur and Sylvester are locked in a bitter rivalry, likely over Mabel or professional standing. ### [F. D. Boyce](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/f_d_boyce) _professional_ Arthur and Boyce are colleagues or partners in some enterprise, working together against Sylvester. ### [F. D. Boyce](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/f_d_boyce) _professional_ Arthur and Boyce are colleagues or partners in some enterprise, working together against Sylvester. ### [Lewis](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/lewis) _professional_ Lewis is Arthur's assistant or servant, carrying out his orders. ### [Mr. Allery](https://www.betterreads.dev/discover/the_wrong_letter_se/characters/mr_allery) _professional_ Arthur and Mr. Allery interact in a business or legal context, often with tension. ## In the story ### [I: The Crime](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/i-the-crime) Superintendent at Scotland Yard who receives the initial murder call and later works with Collins at the crime scene. ### [II: Speculations](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/ii-speculations) Participates in the discussion, questions Lewis's behavior, and agrees to check Collins's facts. ### [IV: The Missing Letter](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/iv-the-missing-letter) Reads Sir James's letter, decides to withhold it from Collins, and goes to Leveson Square to oversee the search. ### [A Mysterious Visit](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/v-a-mysterious-visit) Sinclair presents evidence against Lewis, including his flight and a revolver, and shares the mysterious note found in Collins's flat. ### [VI: At Leveson Square](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/vi-at-leveson-square) Accompanies Collins to the scene; discusses the bullet findings with the doctor; deflects blame for press leaks; relieved that Boyce does not know about the letter. ### [A Confession](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/ix-a-confession) Expresses doubt about Jackson's guilt and shares a moment of silent agreement with Collins. ### [XIV: Back in London](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/xiv-back-in-london) Sinclair is in a genial mood, unconvinced of Jackson's guilt, and points out flaws in the case. He later hints that he understands Collins's mysterious claim. ### [XV: The Crisis](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/xv-the-crisis) Accompanies Collins, is initially sulky but later listens to the explanations, and reminds the group that the murder remains unsolved. ### [XVI: The Criminal Found](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/xvi-the-criminal-found) Lays out his investigation and deductions, finally naming Collins as the murderer and taking urgent action. ### [XVII: The Wrong Letter](https://www.betterreads.dev/discover/the_wrong_letter_se/chapters/xvii-the-wrong-letter) Presents the discovered letter and argues for avoiding a public scandal. ## Links - HTML: https://www.betterreads.dev/discover/the_wrong_letter_se/characters/arthur_sinclair - Book: https://www.betterreads.dev/discover/the_wrong_letter_se - All characters: https://www.betterreads.dev/discover/the_wrong_letter_se/characters