Deadly Wives, an Adaline and Genevieve Adventure

Adaline and her sister, Genevieve, living in Victorian London, are the new brides of Lord Cedrick's twin sons Addison and Garrett. Weeks later Lord Cedrick is brutally murdered in his sleep, his throat cut from ear to ear. The Scotland Yard detective sent to investigate the murder determined the murder was the result of a home invasion turned wrong.
Adaline and Genevieve disagree with the Scotland Yard detective's theory because the detective found no evidence of forced entry into the house, no jimmied windows or doors, nothing unusual outside the house. Adaline and Genevieve theorize the killer is living in the house with them.
A short time later a maid is murdered in the same manner, also in her sleep. Then another, then another and yet another maid all murdered with her throat slit.
The sisters' investigation into the murders creates a problem for the Scotland Yard's detective.
Their investigation takes them through a series of interviews with the household staff. Their talks reveals more than one staff member has a good reason to see Lord Cedrick dead Adaline and Genevieve determine if the killer is caught, it would be them to catch him. They know failure to catch the killer quickly will result in more maids having their throats cut.
The death toll continues to rise and Adaline and Genevieve still have absolutely no clues what so ever as to the identity of the killer until a shocked, vulnerable and bewildered witness says she saw a nude blond haired angel holding a bloody knife over a dead maid. No one believed the witness; after all, an angel?
Two more murders and another more reliable witness sees a nude blond woman running away from the latest murder scene. The witness cannot identify the woman she saw hurriedly run away.
Adaline and Genevieve and their husbands catch the killer in the act of attacking two more maids, but these lucky maids survive. The identity of murderer who committed these grisly murders is a shock to everyone.