Wilson had waited opposite the building perhaps an hour, lulled into abstraction of thought by the silence of the neighborhood, when he was startled by hearing a piercing shriek, loud and long continued, which then died away, and all was still again. Whether it came from the apartment-house or one of the private dwellings next to it, he was in doubt. That it was a woman's cry he felt sure. Was it a cry of pain, or the shriek of nightmare? He could not tell. That solitary, awful cry, disturbing the death-like stillness, seemed uncanny. It made him shiver and draw his cloak closer about him. If it had only been repeated, after he was on the alert, he would have felt better satisfied; but though he listened intently he heard nothing. Ten minutes later, another thing occurred, which attracted his attention. A light in a window on the fifth floor was extinguished. There was certainly nothing suspicious about this, for lights are usually put out when one retires. He noticed it because it was the only light which showed from any of the windows during his vigil. Whilst he was thinking of this, the door opposite opened and a man emerged. Judging it to be Mr. Mitchel, he hastily followed. That there might certainly be no mistake, Wilson walked rapidly enough to reach the Avenue corner ahead of the man, when he crossed, so timing himself that he passed in front of the other just as they both reached the street lamp. Taking a quick, but thorough look, Wilson saw that it was not Mr. Mitchel, so abandoned the pursuit, going back quickly towards the apartment-house. He had proceeded but a few paces, when he met Mr. Mitchel coming rapidly towards him. Breathing a sigh of relief, he passed, then crossed the street, and with his usual skill readily kept Mr. Mitchel in sight till he entered the Fifth Avenue Hotel. Wilson saw him take his key and go up-stairs, so that he felt that his vigil was over for that night. Looking at his watch he noted that it was just one o'clock. Going into the reading-room he wrote a report of the day's occurrences and then calling a messenger, sent it to head-quarters addressed to Mr. Barnes. This done he felt entitled to hurry home for a short sleep--short, because he knew it would be his duty to be on the watch again the next day, and until he received further instructions from Mr. Barnes. Mr. Barnes had immediately after his arrival obtained the requisition papers for which he had telegraphed, and which he found awaiting him. With these he had returned to Boston the same day, and obtaining his prisoner succeeded in catching the midnight train once more, arriving in New York with the loss of but a single day from the new case which so absorbed all his interest. Thus the morning after that on which the jewel robbery had been discovered he entered his offices quite early, having delivered his prisoner at police head-quarters.