Mr. Medwin bowed, his close-set eyes travelling swiftly over the other occupants of the room. "Good morning," he said, in that peculiarly suave voice of his. "May I inquire what all this signifies?" "Professor Carter has been murdered." Marsden's answer came with startling bluntness, and there could be no question as to the effect that it produced. An expression of incredulous amazement flashed across the big man's face, and for a moment he stood gripping his hat and staring blankly at the speaker. "Murdered?" he exclaimed at last. "Impossible! There must be some mistake." "It's not the sort of thing that lends itself to mistakes," returned the detective. Mr. Medwin drew in a long breath, and Colin, who was watching intently, saw that he was making a tremendous effort to recover his self-control. "I think I had better sit down for a moment," he said slowly. He moved forward, and, laying his hat on the corner of the table, sank into the vacant chair from which Marsden had just arisen. "You must excuse me," he continued. "I feel half stunned at this appalling news. The Professor was one of my most valued friends." He moistened his lips and glanced up suddenly at the detective. "When did it happen?" he demanded. "Last night," was the reply, "or, to be more exact, about a quarter to one this morning." "Why wasn't I sent for before?" Marsden stroked his moustache, and eyed the other with a kind of dispassionate interest. "Well, Mr. Medwin, I appreciate the importance of your testimony, but as I happen to be responsible for this case you must permit me to conduct my investigation in the way that I consider best." Instead of betraying any resentment at the snub, the solicitor merely nodded. "Quite so," he assented readily. "Your first step would naturally be to go into all the circumstances of the murder, and I was forgetting for a moment what a great deal of work it must have entailed." He paused. "Have you made any discoveries?" he asked. "Anything that could possibly be described as a clue?" "Several," replied Marsden. "But I think it will save time if I give you the full details straight away. There are several peculiar features about the affair, and it's not much use discussing them until you are in possession of the facts." Mr. Medwin folded his arms. "Just exactly as you prefer," he remarked. "Please consider me entirely at your service."