End of the Line — George Douglas

There had to be a good reason why old Miss Harvill, of the Dower House, Fenton, was killed. The trouble was there were too many suspects. Detective Inspector Lynn, the officer in charge of the case, finds complications arising when some of the girls from Fenton Manor School seem to be implicated in odd incidents in the vicinity of the Dower House. When one of the girls goes missing, a clever piece of observation, aided by specialised knowledge, leads a constable to what proves to be her grave...