There was no doubt that someone had left the parcel in the letter box within the hour. According to Maxwell, it had not been there when he last looked in; according to Robert, he had not been out of the policeman's company since he left the sitting-room. Who, then, placed this damning evidence of the crime in the box? The assassin himself? But the assassin, as had been proved clearly, was a negro. A few questions to the constable stationed near the door had elicited the fact that no negro had gone up. In fact, the man had sworn that he had seen nobody ascend the stairs since the time Fanks returned from his unsuccessful pursuit. So scanty were the facts which he had to go on, that Fanks could not even build up a theory. He was completely in the dark, and he seemed likely to remain so. The instrument was of silver, the length of a darning needle, and while the point was as sharp as a lancet, it broadened gradually till when it passed into a slim, ebony handle, it was--for a needle, quite bulky. In this broad part the poison was doubtless contained, and thence it oozed, drop by drop, to the deadly point. Fanks shuddered at the sight of the piece of devilish ingenuity. The infernal dexterity of the thing gave him an idea. "Must have been manufactured by a scientific man," he mused, touching the slender, silver line gingerly. "It's too clever for an amateur. Louis, the new baronet, is a man of science; he has succeeded to the title. Can it be that--but, no!" he added, breaking off abruptly, "he would not commit a crime in so obvious a fashion, much less, leave the means he used at the address of his victim." Nevertheless, the idea lured him so far afield, into so many speculations that, finding they led to nothing, he locked up the poisoned needle, put it out of his thoughts, and paid a visit to New Scotland Yard. Here he explained to the person in authority, that, while he had every hope of capturing the assassin of the late Sir Gregory Fellenger, yet he was bound to point out that the expenses of the case would be considerable. To this, the person in authority replied by placing before Fanks a letter from Messrs. Vaud and Vaud, of Lincoln's Inn Fields. It stated that they had been directed by Sir Louis Fellenger--who was at present confined to bed through ill-health--to assure the authorities that he wished every effort to be made to discover the murderer of his cousin; and that he would willingly bear the costs of the investigation. This communication concluded by requesting that the detective in charge of the case should call at the offices of the lawyers at his earliest convenience. "Very meritorious of Sir Louis to save the Government expense," said the person in authority. "Use what money you require, Mr. Fanks, but be reasonable--be reasonable." "I shall be as reasonable as I possibly can be, sir," replied Fanks; "but in my opinion, the case will be both long and expensive. It is the most complicated matter that I ever took in hand."