All the same, his hint about the knife dwelt in her memory. It was indeed, strange, that the police authorities had not followed up this important clue. Without doubt, if the knife was a peculiar one, which Neddy hinted, its owner might be discovered; and once he was found, then the truth would become known. Miss Lemby retired to bed on that night resolved to see Sergeant Purse on the morrow and learn what she could. Having been engaged to Sir Hector, there was ample excuse for her to ask questions. In the anxiety and interest caused by Neddy's conversation Claudia quite forgot her tussle with Lady Wyke, and passed a better night in consequence. By three o'clock next day she found herself standing with her bicycle before the door of the Redleigh Police-office, and entered to ask for the sergeant. Luck stood her friend, for the sergeant, usually out on his rounds, happened to be in and disengaged. Claudia was admitted into the sanctum of the official, and was amiably received by the foxy-faced little man. As usual, he was as dry as a mummy in his looks, and his eyes were more than ever like those of a rat. He was uncommonly polite to Miss Lemby, since he knew her story, and was sorry for her. "I hope you've got over it, miss," said the sergeant, placing a chair for his visitor. "It was a hot time for you, that same murder." "I am getting over it," Claudia assured him with a faint smile. "And it was a very painful time as I respected Sir Hector." "I don't think he behaved very well, Miss Lemby." "Oh, I think he did. After all, sergeant, he did not know that his wife was alive, you know. It was all a mistake. But I have called to ask if you have a clue to the assassin?" "No, Miss Lemby. I quite understand why you should come and ask, as naturally, you'd like to see the villain hanged. Lady Wyke would like to see it also. I can't catch him, however. He went off on that bicycle, and vanished into thin air, like those witches in the play." "Well, Mr. Purse. I have been thinking over the matter," said Claudia, with diplomatic frankness, "and it occurred to me that you should follow the clue of the knife. You have it, I believe?" "Oh, yes," Sergeant Purse rose and went to a shelf at the further end of his office to fumble there, "but I don't see, how we can follow that clue." "Why not? Someone told me that the knife was a peculiar one. Can't you trace it to the shop where it was bought?" "It's an idea certainly, Miss Lemby," said Purse, returning with a parcel in his hand. "Look at the knife yourself. It is a peculiar one." He untied a string and unrolled several sheets of paper. Then Claudia saw a sailors clasp-knife with a handle of black bone decorated with three broad stripes of inlaid silver. "This is the knife, Miss Lemby." said the officer. Claudia gasped and felt herself grow faint. The knife belonged to her father. CHAPTER XIX.