In the unpublished short story The Incident of the Dog's Ball, James Graham is the nephew of Matilda Wheeler. He works as junior partner in "some chemical dye works" and lives in London but made regular trips to visit his aunt at Little Hemel in Kent.
James was one of the benficiaries of his aunt's will. However, after she had an accident and fell down the stairs, she decided to make a new will which disinherited him and her other relative, her niece Mollie Davidson. Shortly thereafter, she died.
Investigations by Poirot revealed that Miss Wheeler had shown the new will to James, from which he surmised that she suspected that James was the one who had pushed her down the stairs and was trying to kill her. She might have expected him to share the details of the will with Mollie but in the event he did not. Despite some other suspicious indications, for example, James was irate when Poirot suggested an autopsy on Miss Wheeler, Poirot in the end exoneratd James largely because he lacked a motive.
Agatha Christie's Notebook 66 contained brief sketches of the characters Christie was planning for the story. Here, she planned for James to have the surname "Grant". He was to be "prim and proper" and to have a fiancee, a hospital nurse Miss O'Gorman.[1] Presumably to throw some suspicion on him--suggesting he could get poisons from the hospital. In the event Jame's surname was changed to Graham. The "prim and proper" description never made it into the text and he did not have a fiancee. He did however gain an occupation. The researcher John Curran in a footnote in Agatha Christie's Secret Notebooks: Fifty Years of Mysteries in the Making comments that Christie was unusually specific in describing his occupation. Working in a chemical dye works would be suspicious in a poisoning case but in the event, this "clue" is only mentioned once and never referred to again.[2] The same notes sketch another character, a journalist, Ted Weedon, who had been in prison because he forged his uncle’s name in a cheque. He owed money to an actress who was pressing him for repayment. Presumably this was a second nephew. This character never made it into the story.
When Agatha Christie later expanded into the short story into the full length novel Dumb Witness, she used a parallel character Charles Arundell in place of James Graham. The backstories are similar but not the same. Charles had a bad reputation and a track record as a forger and had forged cheques by his aunt (thereby borrowing characteristics from the "Ted Weedon" above. He had also quarreled with her aunt when she refused to lend him money, and had even threatened her life. By contrast, in this short story, the only negatives we have of James are Miss Lawson's description of him as "very rude", and Poirot commenting that his personality is "not the most charming".