The above conversation serves to show that the police, on their side, were becoming seriously worried. They had hoped that the strong presumptive evidence against Walter Brooklyn would speedily have been reinforced by further discoveries; but so far they had been disappointed. Inspector Blaikie at least was still strongly of opinion that he was guilty; but a strong opinion is not enough to convince a jury, and the inspector did not like to see the acquittal of a man he had arrested, especially as he had no other evidence pointing to some different person as the guilty person. Superintendent Wilson at least, while he could not blame the inspector for his conduct of the investigation, was growing more and more dissatisfied with the progress of the case. He had an uneasy and a growing feeling, which he had at first been unwilling to admit even to himself, that they were on the wrong tack. Chapter XX Superintendent Wilson Thinks It Out When the inspector had left him, Superintendent Wilson gave himself up for a time to his thoughts. Leaning back in his chair, with his long legs stretched out before him, and the tips of his fingers pressed together before his face, he concentrated his faculties upon the Brooklyn affair. A heavy frown settled on his brow, and he gave every now and then an impatient twist of his body, eloquent of his mind’s discomfort. At length he sighed, looked at the clock, rose, put on his hat, and started for home. He had made up his mind, as he did when difficulties beset him, to talk the case over with his wife. Superintendent Wilson never mentioned business to his wife when things were going well; but whenever his usually clear brain seemed to be working amiss, it was his way to unload on her all his trouble. Not that Mrs. Wilson had a powerful intellect—far from it. She was a comfortable, motherly woman, inclined to stoutness, and completely wrapped up in her children and her home. For her husband she had a profound admiration. He was, to her mind, not merely the finest detective in Europe, but the cleverest man in the world. But she was quite content to admire his cleverness without understanding it; and her husband made no attempt, as a rule, to discuss his cases with her. He had found, however, that on the rare occasions on which his thinking got into a blind alley, her very passivity was the best possible help he could have. As he talked to her, and as she assented unquestioningly to everything that he said, new ideas somehow arose in his mind. Doubts were dispelled, new courses of action suggested, the weak spots in the armour of crime became apparent. He would tell her that she had been the source of his most brilliant inspirations; and she would placidly accept the rôle, without bothering to inquire in what way she contributed to his flashes of insight into the most abstruse mysteries that came under the notice of the Criminal Investigation Department.