Murder by the Clock by Rufus King — Read

Mrs. Endicott thought for a moment of simply dialling the operator and saying, "I want a policeman."

It was what the printed notices in the telephone directory urged one to do in case of an emergency. But it wasn't an emergency exactly, nor -- still exactly -- was it a policeman she wanted. She wanted a detective, or an inspector, or something; a man to whom she could explain her worry about Herbert, and who could do something about it if he agreed with her that Herbert was in danger.