"Who placed this five hundred to your credit?" asked Naball. "I don't know." "You don't know?" echoed Naball, in surprise. "Do you mean to say that a large sum like that was placed to your credit by a person whom you don't know?" "I do." "And I can substantiate that statement," said Ezra quietly. Naball looked from one to the other in perplexity, puzzled what to ask next. Then he felt the only thing to be done was to go away and think the matter over. But he did not intend to lose sight of Keith, and this absurd statement about the five hundred only seemed to strengthen his suspicions, so he determined to have him shadowed. "Thank you, Mr. Stewart," he said quietly. "I have nothing more to ask. What time did you say you were going to meet a country train?" "I mentioned no time," replied Keith sharply. Baffled by this answer, Naball tried another way. "Will you kindly give me your address?" he asked, pulling out his pocket-book. "I may want to communicate with you." "Vance's boarding-house, Powlett Street, East Melbourne." Mr. Naball noted this in his book, and then, with a slight nod, took his leave. "Damn him," cried Keith fiercely, "he suspects me of this crime." "Pooh! that's nonsense," replied Ezra, as they went out, "you can easily prove an alibi." "No, I can't," replied Keith, in a hard tone. "From half-past twelve o'clock till two I was by myself, and no one saw me. I say I was wandering about the streets, he thinks I was in Russell Street committing a murder." "I don't think you need be a bit afraid of anyone suspecting you," said Ezra bitterly. "Why, they might as well think I killed my father." "You!" "Yes. I had a quarrel with him, and then he was murdered. Oh, I assure you they could get up an excellent case against me." "But you could prove an alibi." "That's just where it is," said Ezra coolly; "I can't." "Why not?" "Because, after leaving Kitty Marchurst, I went down the street to _The Penny Whistle_ office, and found it closed. I then walked home along Collins Street, through the Fitzroy Gardens. It was a beautiful night, and, as I was thinking over my quarrel with my father, I sat down on one of the seats for a time, so I did not get home till two o'clock in the morning. No one saw me, and I've got quite as much difficulty in proving an alibi as you have." "Do you think Naball suspects you?" "No; nor do I think he suspects you, but I've got a suspicion that he suspects some one." "And that some one--" "Is called Randolph Villiers." CHAPTER XVIII. CIRCUMSTANTIAL EVIDENCE. When Naball left the two young men, he went straight to the Detective Office in order to get some one to look after Keith Stewart, and see that he did not leave Melbourne. Naball did not believe that he was going to meet any one that night, and wanted to find out why he was going to the station.