E. Phillips Oppenheim 
The Wicked Marquis [EPUB ebook] 

Wealthy playwright and playboy Jermyn Annerley is smitten by the beautiful and talented actress Sybil Cluley. She is very successful but her life is devoted to the care of her young sister who has been ill. At Jermyn’s country estate, Sybil runs into Lord Lakenham, a roguish playboy who is equally in love with her, but also knows something of her past. Jermyn proposes, much to the chagrin of his lovely cousin Lucille, who has had her eye on him for many years. Lakenham and Lucille conspire to end the engagement. Sybil is broken hearted but puts her sister’s welfare above her own. Then Lakenham is murdered in the billiard room. A romance has become a murder mystery.