"Good God!" he stammered. "Is this true? Are you certain of it?" "I am quite certain of it--now," was the answer. "I have suspected it was so for the last two days, but what I have found out this morning puts the matter beyond question." He took hold of a chair and thrust it toward Colin. "Sit down for a moment, doctor. I know how impatient and anxious you must be feeling, but I can assure you that I sha'n't waste a second. Before we go any further it's essential that you should hear the truth." "Get on with it, then," said Colin hoarsely. "I don't want a chair. I'd rather stand." Marsden walked across to his desk and seated himself in front of an open cardboard file, containing a number of papers. "Do you remember what I told you the morning after the murder?" he asked. "That if we could find the Professor's old servant, Kennedy, we should probably learn something which would alter our whole view of the case?" Colin nodded. "Well, a couple of days ago I got a message from the Hertford police that they had run him to earth in a small village near Hoddesdon. He has been paralyzed and bedridden for some months, and as the old woman who has been looking after him can't even read or write, he might easily have died without ever hearing of the murder. As it was, we got hold of him just in time. I went down there yesterday, and, although he was so ill that he could hardly speak, he managed to give me the one bit of information that I was so badly in need of. He told me that twenty-three years ago Nancy Carter, the Professor's only daughter, then a girl of eighteen, had run away from her home and married a young artist called Richmond Seymour." Colin took a step forward, but before he could speak the detective raised his hand. "Let me finish first, and then I'll answer any questions you like. It seems from Kennedy's story that the Professor was one of those self-willed, obstinate sort of people who simply don't know the meaning of the word 'forgiveness.' He had forbidden this marriage, and, since his daughter had chosen to disobey him, he made up his mind that he would have nothing more to do with her. Kennedy tells me that from that time forward he never even mentioned her name again. "Well, to cut a long story short, as soon as I heard this the two names 'Nancy Seymour' came back to my mind at once. I'd written them down in my notebook that day in the King's Road, and somehow or other they'd stuck in my memory ever since. I knew nothing about the young lady except the fact that she'd helped to save me from having my face kicked in, but I guessed it was likely that you two had kept in touch with each other, and so directly I got back to town I 'phoned you to come up." He paused. "I thought you'd probably be able to give me some information, doctor, and, by God, you did." Colin came across to the desk, and, leaning over the back, stared eagerly in the detective's face.