"Oh, how do you know that? By a very curious thing. One of the notes placed in the safe on the night of the murder was endorsed by the office-boy with the words 'Back Flat-Iron,' and strange to say the endorsed note has turned up." "And that is it?" "Exactly. Now, do you understand?" Kitty shrugged her shoulders. "I understand that you have secured an excellent piece of evidence, nothing more. Where did you get the note?" "From Miss Rainsford." "From Miss Rainsford!" repeated Kitty in surprise; "but you surely don't suspect--" "No, I don't," interposed the detective; "because she was able to tell me where she got the note from." "Well, I presume she got it from me." "Yes," replied Naball, rather surprised at this cool admission. "She received it yesterday from you." "Oh! then, you think I'm guilty?" "Not if you can tell me where you got the note from." "Certainly I can--from Mortimer--paid to me the day before yesterday." "Your salary?" "Not exactly," answered Kitty; "if it had been, you'd never be able to trace the note further back. No; I was at the theatre in the morning, and found myself short of money, so I asked Mortimer for some. He gave me that five-pound note, and, as he took it, from his waistcoat pocket, I've no doubt he'll be able to recollect from whom he received it." "Why?" "Because Mortimer doesn't carry fivers in his waistcoat pocket generally," said Caprice impatiently, "so he must have put that note there for some special reason. You'd better go and ask him." "Certainly," said Naball, and arose to his feet. "I'm very much obliged to you." "Then you don't think me guilty?" asked Kitty, with a smile. "Upon my word, I don't know what to think," said the detective dismally. "The whole case seems mixed up. I'll tell you when I find the man who can't account for the possession of this fiver." Kitty smiled, and then Naball took his leave, going straight from Toorak to the Bon-Bon Theatre, where he found Mortimer in his sanctum, up to the ears in business, as usual. "Well, Naball," said the manager, looking up sharply, "what's up? Look sharp, I'm awfully busy." "I only want to know where you got this?" asked Naball, giving him the five-pound note. Mortimer took it up, and looked perplexed. "How the deuce should I know; I get so many. Why do you want to know?" "Oh, nothing. I just want to trace the note. Caprice said you gave it to her the day before yesterday." "Eh! did I?" "Yes. You took it from your waistcoat pocket." "Of course; to be sure, she wanted some money. Yes; I kept it apart because it was made money--won it off Malton at euchre." "Malton!" repeated Naball in amazement; "are you sure?" "Yes, quite. You know I'm generally unlucky at cards, and this is about the first fiver I've made, so I kept it just to bring me luck; but Caprice wanted money, so I handed over my luck to her. There's nothing wrong, eh?" "Oh, dear, no," replied Naball; "not the slightest--only some professional business."