The Death-Cap Dancers

1981 St. Martin's Press trade paperback, Gladys Mitchell (Speedy Death). While en route to visit relatives, Hermione Lestrange falls into company with three agreeable women who are spending their autumn holiday in a forest cabin. Out for a drive, the group discovers a battered bicycle by the side of the road, and closer inspection reveals the unfortunate owner, seemingly dead from head wounds, her body found in a nearby ravine. The police are contacted, but Hermione becomes concerned that suspicion may fall on herself and her new acquaintances, as the scene resembles a hastily covered-up automobile accident. Fearing the worst, she rings up her great-aunt and voices her fears. - Amazon