The Old Man in the Corner by Baroness Emma Orczy

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. He narrates all this information, while tying complicated knots in a piece of string, to a female Journalist who frequents the same tea-shop (the ABC Teashop on the corner of Norfolk Street and the Strand). They enjoy an antagonistic relationship, as the Journalist attempts to cut the Old Man's ego down to size and the Old Man trumps her every time.

--Wikipedia