Monsieur Lecoq by Emile Gaboriau

The extreme uncertainty of the result was another attraction for M. Segmuller's investigating mind. Given the magnitude of the difficulties that were to be overcome, he rightly considered that if his efforts proved successful, he would have achieved a really wonderful victory. And, assisted by such a man as Lecoq, who had a positive genius for his calling, and in whom he recognized a most valuable auxiliary, he really felt confident of ultimate success.

Even on returning home after the fatiguing labors of the day he did not think of freeing himself from the burden of responsibility in relation to the business he had on hand, or of driving away care until the morrow. He dined in haste, and as soon as he had swallowed his coffee began to study the case with renewed ardor. He had brought from his office a copy of the prisoner's narrative, which he attentively perused, not once or twice, but several times, seeking for some weak point that might be attacked with a probability of success. He analyzed every answer, and weighed one expression after another, striving, as he did so, to find some flaw through which he might slip a question calculated to shatter the structure of defense. He worked thus, far into the night, and yet he was on his legs again at an early hour in the morning. By eight o'clock he was not merely dressed and shaved, he had not merely taken his matutinal chocolate and arranged his papers, but he was actually on his way to the Palais de Justice. He had quite forgotten that his own impatience was not shared by others.