Unnatural Causes by P.D. James

For Superintendent Adam Dalgliesh it was supposed to be a vacation, a few days spent with his Aunt Jane at her cottage on the Suffolk coast. But, as always seems to happen in these instances, fate had other ideas. It begins the night of his arrival with a gathering of his aunt’s neighbors it seems one of their number, detective novelist Maurice Seton has gone missing.

Superintendent Dalgliesh can barely finish telling them that he, as a member of London’s Metropolitan Police, has no jurisdiction in this part of England (besides which he is supposed to be on vacation) when word reaches them that Maurice Seton has been found. Found dead with his hands chopped off and floating off the shore in a dinghy. So much for a peaceful vacation.