Anna Katherine Green 
X. Y. Z. A Detective Story [EPUB ebook] 

One of the first writers of detective fiction in America, distinguished by well plotted, legally accurate stories.She is credited with shaping detective fiction into its classic form, and developing the series detective. Her main character was detective Ebenezer Gryce of the New York Metropolitan Police Force, but in three novels he is assisted by the nosy society spinster Amelia Butterworth, the prototype for Miss Marple, Miss Silver and other creations. She also invented the ‘girl detective’: in the character of Violet Strange, a debutante with a secret life as a sleuth.