A January Killing: Detective Inspector Zig Batten 2

"Goodness, there's some beautiful writing here!" January, white frost, a pitch-black orchard. The ancient ritual of 'Wassailing' begins with a torchlight procession. It ends with shotguns being fired into the trees, to scare off 'evil spirits' and revive the apple blossom.
But not every shotgun fires blanks, and next day a dead body has blossomed in the orchard.
What is the killer's motive? Why this victim? And who is sending anonymous letters to the villagers of Stockton Marsh, where Detecti...