Death of a Poison Pen (Hamish Macbeth Mystery #19) by M. C. Beaton
New mass market paperback (cover may vary).
From the author of the Agatha Raisin television series...
Death of a Poison Pen: A Hamish Macbeth Mystery
When the residents of Lochdubh begin receiving poison pen letters, no one takes them seriously. But Constable Hamish Macbeth fears them, and his instincts prove correct when the postmistress is found hanging from a rope with a vicious poison pen letter at her feet.