The Man in the Brown Suit by Agatha Christie

The novel "The Man in the Brown Suit", published in 1924, is one of Agatha Christie's early works. Adventure-loving Anne Bedingfield, the orphaned daughter of an anthropology professor, witnesses an accident on the London Underground. On the same January day, in another part of the city, in the mansion of the wealthy Sir Eustace Pedler, the body of an unidentified foreigner is found. In these two seemingly unrelated cases, the same Man in the Brown Suit appears. To solve the mystery, Anne is ready to do the most insane things, even clashing with the head of the criminal world and reaching the inaccessible outskirts of South Africa.