Wilkie Collins 
My Lady’s Money 

This is a delightful tale of a woman of means who becomes the victim of the theft of a 500 pound note in her home. There are a number of possible suspects and she obtains help in pursuing the perpetrator. She retains a young girl as her companion and as she is of much lower rank and may be looked on as the possible thief, she is sent away to her Aunt, Miss Pink, to live until the manner is resolved. (Goodreads)