A Clue in Wax by Fred M. White

Clifford Cheriton was, however, not destined to get clear of London quite as soon as he expected. On the face of it, all that he had to do was to hand in his resignation and take leave of his colleagues within the next seven days. But when he presented himself at Scotland Yard on the Monday morning his superior officer greeted him with the curt information that there was a rather important piece of work to be done and that he, Cheriton, must think himself exceedingly lucky to have part of it placed in his hands. He looked at Inspector Merrick in dismay.

"Well, what is biting you now?" the latter rasped. He was one of the older school that is fast dying out and believed in direct methods. A man of little education who had obtained his present post partly by influence and partly by a sort of dogged determination which had often led him to follow up successfully a clue that cleverer men had abandoned. "You look at me as if I had done you a mischief, instead of putting a real class job in your way. What's the matter with you?"