The Essence of Malice (Amory Ames #4)
Ashley Weaver

The more Amory and Milo look into the motives of industry rivals and the Belanger heirs who are vying for control of his perfume empire, the more they are convinced that Madame Nanette may be right. When secrets unfold and things take a dangerous turn, Amory and Milo must work quickly to uncover the essence of the matter and catch a killer before the scent goes cold.