That Affair Next Door (Version 2)

Published in 1897, 'That Affair Next Door' by Anna Katharine Green features the astute Miss Butterworth, who witnesses a mysterious event from her window. After seeing a man and woman enter a neighboring mansion, she is drawn into a murder investigation when only the man exits shortly after. This novel is notable for its early contribution to the detective fiction genre, showcasing Green's intricate plotting and character development.