Investigating magistrate since 1859, he had rapidly acquired the most brilliant reputation.  Laborious, patient, and acute, he knew with singular skill how to disentangle the skein of the most complicated affair, and from the midst of a thousand threads lay hold to the right one.  None better than he, armed with an implacable logic, could solve those terrible problems in which X—­in algebra, the unknown quantity—­represents the criminal.  Clever in deducing the unknown from the known, he excelled in collecting facts, and in uniting in a bundle of overwhelming proofs circumstances the most trifling, and in appearance the most insignificant.

Although possessed of qualifications for his office so numerous and valuable, he was tremblingly distrustful of his own abilities and exercised his terrible functions with diffidence and hesitation.  He wanted audacity to risk those sudden surprises so often resorted to by his colleagues in the pursuit of truth.

Thus it was repugnant to his feelings to deceive even an accused person, or to lay snares for him; in fact the mere idea of the possibility of a judicial error terrified him.  They said of him in the courts, “He is a trembler.”  What he sought was not conviction, nor the most probable presumptions, but the most absolute certainty.  No rest for him until the day when the accused was forced to bow before the evidence; so much so that he had been jestingly reproached with seeking not to discover criminals but innocents.

The chief of detective police was none other than the celebrated Gevrol.  He is really an able man, but wanting in perseverance, and liable to be blinded by an incredible obstinacy.  If he loses a clue, he cannot bring himself to acknowledge it, still less to retrace his steps.  His audacity and coolness, however, render it impossible to disconcert him; and being possessed of immense personal strength, hidden under a most meagre appearance, he has never hesitated to confront the most daring of malefactors.

But his specialty, his triumph, his glory, is a memory of faces, so prodigious as to exceed belief.  Let him see a face for five minutes, and it is enough.  Its possessor is catalogued, and will be recognised at any time.  The impossibilities of place, the unlikelihood of circumstances, the most incredible disguises will not lead him astray.  The reason for this, so he pretends, is because he only looks at a man’s eyes, without noticing any other features.

This faculty was severely tested some months back at Poissy, by the following experiment.  Three prisoners were draped in coverings so as to completely disguise their height.  Over their faces were thick veils, allowing nothing of the features to be seen except the eyes, for which holes had been made; and in this state they were shown to Gevrol.

Without the slightest hesitation he recognised the prisoners and named them.  Had chance alone assisted him?

The subordinate Gevrol had brought with him, was an old offender, reconciled to the law.  A smart fellow in his profession, crafty as a fox, and jealous of his chief, whose abilities he held in light estimation.  His name was Lecoq.