Old Man in the Corner
Created by Baroness Orczy, author of the famous Scarlet Pimpernel series, The Old Man in the Corner was one of the earliest armchair detectives, popping up with so many others in the wake of the huge popularity of the Sherlock Holmes stories. The Old Man relies mostly upon sensationalistic "penny dreadful" newspaper accounts, with the occasional courtroom visit for extra laughs. He narrates all this information (while tying complicated knots in a piece of string) to a Lady Journalist who frequents the same tea-shop. (Summary from Wikipedia)