Before revision: In The Adventure of the Abbey Grange (1904), Sherlock Holmes investigates the murder of Eustace Brackenstall A whodunit or whodunnit ( a colloquial elision of "Who [has] done it?")
After revision: In The Adventure of the Abbey Grange (1904), Sherlock Holmes investigates the murder of Eustace Brackenstall A whodunit (less commonly spelled—or misspelled—as whodunnit; a colloquial elision of "Who [has] done it?")