The Black Gang by H.C. McNeile

Sir Bryan Johnstone leaned back in his chair and stared at the ceiling with a frown. His hands were thrust deep into his trouser pockets; his long legs were stretched out to their full extent under the big roll-top desk in front of him. From the next room came the monotonous tapping of a typewriter, and after a while Sir Bryan closed his eyes.

Through the open window there came the murmur of the London traffic -- that soothing sound so conducive to sleep in those who have lunched well. But that did not apply to the man lying back in his chair. Sir Bryan's lunch was always a frugal meal, and it was no desire for sleep that made the Director of Criminal Investigation close his eyes. He was puzzled, and the report lying on the desk in front of him was the reason.