The Tree of Death by Brian Eastman
When Laura Thyme goes to the parish of Baffington to visit her cousin's recently ordained son, she meets many of the locals...and witnesses the sudden death of one of them. A year later, Rosemary and Laura return to help with an ambitious Medieval Fayre, organised by the local celebrity and historian, Franklin Danvers. Their task is to refurbish the neglected churchyard, where the finest feature is a huge old yew tree. However, on their first morning they discover the body of a man under the tree, pierced through the heart by an arrow. Unfortunately, most of the villagers had just received tuition in archery, and several of them had proved to be excellent shots! Almost everyone - including the vicar - had motive, means and opportunity galore, so Rosemary and Thyme must weed through a village full of suspects to uncover the true murderer...