Swallow Them Up — Gavin MacDonald

A young woman's body is found in woodland near Edinburgh but no-one of that description is on a missing list. When Chief Inspector Forsyth solves that mystery, it becomes clear that the death is connected with an amateur theatrical company. The man who ran the company is found dead after being tortured and the death of one of the sponsors follows. It seems clear that someone is taking revenge for the death of the young woman and, though everyone else is baffled, Forsyth applies logical deduction to arrive at the name of the killer