Book ~ "Killer Fudge" (2012) Mary Kay Andrews (Kathy Hogan Trocheck)

From Goodreads ~ Atlanta private investigator/cleaning business owner Callahan Garrity once again proves her ability to clean up a sticky mess. When the grandson of faithful House Mouse employee Ruby is charged with brutally bludgeoning an elderly antique dealer, Callahan is called on to investigate. What she discovers is a recipe for homicide. 

Callahan used to be a police officer and changed careers when she bought House Mouse, a cleaning service that she runs with her mother, Edna ... but she still does private investigating on the side.

Ruby, one of Callahan's House Mouse employees, comes to her for help ... her young grandson had been arrested for the murder of an elderly client he had been hired to do lawn work for.  Plus he'd taken a pile of cash from the old man.  Callahan investigates and discovers what really happened.  The solving of the real killer is pretty lame.

This is a short story in the Callahan Garrity Mystery Series. 

 Also included is a recipe for a fudge.