A week after the murder was committed, Policeman X (as it is not of an individual, but of a system, we complain, we will not make this particular constable's name more prominent than it has already become)--a week then after the murder was committed, Policeman X, in private clothes, saw lurking in the vicinity of Great Porter Square, a man: as he might see to-night other men lurking in the vicinity of any and every square in London. It is a peculiarity of policemen in private clothes that they are always ready to suspect, and that in their eyes every poor-looking person with whose face they are not familiar is a disreputable character. Policeman X watched this man for a few moments, and took the opportunity of brushing past him when they were near a lamp-post. The man's face was unknown to him; it was haggard and pale, and his clothes betokened poverty. These were terrible signs, and Policeman X at once set himself the task of stealthily following the man, who walked leisurely towards the house, No. 119, in which the murder was committed. The house was deserted and untenanted, as it is at the present time. Now, would the suspected man pass the house, or would he linger near it? Much depended upon this. The man reached the house, peered around (according to Policeman X's statement) to make sure that he was not observed, and then cast his eyes to the dark windows. He lingered, as though in indecision, for a few moments, and standing before the door, appeared to be studying the number. Then he strolled away. It cannot be said that there was anything criminating in these movements, but Policeman X, determined not to lose sight of his man, followed him at a cautious but convenient distance. The man sauntered round the Square, and presently commenced to munch some stale bread and cheese, portions of which were afterwards found upon him. He completed the circuit of the Square, and for the second time paused before No. 119. Again he studied the number on the door, and again he looked up at the dark windows. Not satisfied with his inspection in that direction, he stooped down to the grating above the area, and appeared to listen. Still not satisfied, he ascended the two steps which led to the street door, and tried the handle. Nothing more was needed. "I have the murderer!" thought Policeman X, with a thrill of satisfaction; and without further hesitation, he walked quickly up, clapped his hand on the man's shoulder, and said-- "What are you doing here?" The sudden appearance of a human being out of the shadows probably so startled the suspected man that he did not know what to reply. He thrust his head forward in the endeavour to distinguish the features of the questioner. The next words uttered by Policeman X had more meaning in them. With his hand still on the man's shoulder, he said, sternly-- "Come with me!"