"The Leavenworth Case" by Anna Katharine Green is a detective novel published in 1878. When wealthy merchant Horatio Leavenworth is found shot dead in his Manhattan mansion's library, detective Ebenezer Gryce and lawyer Everett Raymond investigate a locked-room mystery. No one could have escaped before the body was discovered. Leavenworth's two orphaned nieces, a maid, and a mysterious gentleman all become suspects in this groundbreaking American detective story that influenced Agatha Christie and helped establish conventions still used in mystery fiction today. (This is an automatically generated summary.)