The Mischief-Maker by E. Phillips Oppenheim

In the untidy salon of his bachelor apartments in the Boulevard Maupassant Estermen awaited the coming of his master in veritable fear and trembling. In all his experience he had never been compelled to face a crisis such as this. There had been small failures, punished, perhaps, by a sarcastic word or biting sentence. There had been no failure to compare with this one! Herr Freudenberg deliberately, and of his own free choice, was accustomed to take huge risks. When they came he accepted them, but when they were not inevitable he as sedulously avoided them. The wrecking of Julien's apartments in the Rue de Montpelier was by far the most hazardous enterprise which had been attempted since the days of the toymaker's first secret visits to Paris. Half a dozen human beings had been done to death in a manner which invited and even challenged the attentions of the French police. A terrible risk had been run and run in vain.

The blow had been struck at the very moment when its object was unattainable! Estermen shivered as he tried to imagine for himself the coming interview. Gone, he feared, was his life of pleasant luxury among the flesh-pots and easy ways of Paris; his bachelor apartments, occupied in name by him but of which the real tenant was his dreaded master. And behind all this apprehension lurked another grisly and terrible fear! For the twentieth time during the last few minutes he peered through the closely drawn Venetian-blind, and his blood ran cold. On the pavement opposite, before the small table of a cafe, a man was sitting -- the same man! For two days he had been there -- a gaunt and silent person with a wonderful trick of gazing away into space from the columns of his newspaper. But Estermen knew all about that! He knew, even, the man's name! He knew that he was one of the most persistent and successful of French detectives. His name was Jean Charles and he had never known failure.