''Six Were Present'' by E. R. Punshon (d. 1956), public domain. It follows Commander Bobby Owen of Scotland Yard as he tackles a seemingly impossible murder tied to African folklore and witchcraft at his childhood estate, Constant Freres.
While on a motoring holiday with his wife Olive, Bobby visits his old ancestral home and his cousin Myra Outers. The setting is steeped in an eerie, Gothic atmosphere featuring ancient ruins and a tall "Folly Tower".
Myra's husband, an expert in African folklore, owns a genuine witch doctor's bag. When a suspect named Val Outers is murdered under impossible circumstances, there are exactly six people present who could have committed the crime.
Bobby's investigation is complicated by the presence of a psychic medium named Teddy Peel, whispered threats, séances, and exotic curses.
Serving as the swansong for Punshon's long-running detective series, the novel offers a sense of circularity and closure to Bobby Owen's life by reuniting him with his roots. The title is recognized as a quintessential example of the traditional British "whodunit," showcasing Punshon's underrated storytelling and distinguished prose.