Death in Retreat — George Douglas

On a day of retreat for clergy at Overdale House, a resident guest, Martin Pender, is foully murdered. The primary task of the Regional Homicide Squad is to track down the bogus parson who joined the retreat. Subsequent events show that serious political motives lie behind the killing, but the basic lead to it all is missing. Then, three young tearaways corner the killer in the woods, and a chess problem, set out on a board, yields vital evidence.