Twist at the End — Steven Saylor

Austin, Texas, in 1885 is a place of dust and dreams, quick riches, and wild desires. But "the Servant girl Annihilators" are also making it a city of fear. The first victim, a mulatto housekeeper, is torn from her bed and murdered. Six more women will die, including pretty blond Eula Phillips, who is bank clerk's Will Porter's lover. Over a decade later, living in New York as O. Henry, Will cannot escape his memories--or a blackmailer's merciless demands. Then a mysterious letter invites him back to Texas to follow the dark path of a sadistic killer and make a stunning discover as he is forced to confront the demons of his own tormented mind...