The unfortunate officer was quite unconscious when found, and although he survived some forty minutes, he never recovered the power of speech, so that he could give no indication as to his assailant. A poker belonging to Mr. Roper was found by his side, and it was inferred that he had entered his room before the attack, and had seized the poker as the only instrument of self-defence within reach. Not the slightest clue was ever obtained which would help to solve this mystery; rewards were offered, but in vain, and the police had at last to confess themselves entirely baffled. Mr. Roper was an exceedingly promising young officer; he had but just completed his course of instruction with considerable credit, and he was said to have been in perfect health and spirits on the fatal evening, so that there was nothing whatever to support, and indeed everything to discredit, any theory of suicide. IX.--A GOOD WORD FOR THE POLICE. Taking a general view of the case as between hunted and hunters, it may be fairly considered that the ultimate advantage is with the latter. Let it be remembered that we hear more of one instance of failure on the part of the police than of ninety-nine successes. The failure is proclaimed trumpet-tongued, the successes pass almost unnoticed into the great garner of criminal reports and judicial or police statistics. At the very least it must be said that we are bound, in common justice, to give due credit to the ceaseless activity, the continual, painstaking effort of the guardians of the public weal. Their methods are the outcome of long and patient experience, developed and improved as time passes, and they have deserved, if not always commanded, success. It may be that the ordinary detective works a little too openly--at least, in this country; that his face and, till lately, his boots were well known in the circles generally frequented by his prey. Again, there may be at times slackness in pursuit, neglect or oversight of early clues. Well-meaning but obstinate men will not keep a perfectly open mind: they may cling too long and too closely to a first theory, wresting their opinions and forcing acquired facts to fit this theory, and so travel farther and farther along the wrong road. "Shadowing" suspected persons does not always answer, and may be carried too far; more, it may be so clumsily done as to put the quarry on his guard and altogether defeat the object in view. But to lay overmuch stress on such shortcomings as these would surely savour of hypercriticism. It is more just to accept with gratitude the overwhelming balance in favour of the police, and give them the credit due to them for the results achieved. [Illustration] Part II. JUDICIAL ERRORS. CHAPTER I. WRONGFUL CONVICTIONS.