Happy Are Those Who Thirst For Justice

Description for HAPPY ARE THOSE WHO THIRST FOR JUSTICE by Andrew M Greeley:

THE HOT-BLOODED HEIRESS has a fantasy. Somebody shoots her rich, domineering grandmother, Violet Enright, aboard her luxury yacht, locks the cabin door, and disappears into the safe, dark waters of Lake Michigan. But when young Fionna Downs' flight of fancy turns perilously real, the dream of a perfect crime turns into a nightmare of scandal and the prospect of long, bleak imprisonment. Wise and gentle Father Blackie Ryan obligingly looks into this pool of turbulent mystery -- with somewhat more than a passing interest. Because someone in Blackie's own family is the killer's next target.

This is #3 in A Father Blackie Ryan Mystery.