"You know him better than that, Mr. Calvert," burst in the professor. "He is engaged to Miss Baldwin, the great friend of the young lady whom you are to marry." Arnold turned on the Greek sharply. "How do you know that?" "I live in a house near Mrs. Baldwin. She is my landlady. I know Tracey and Miss Baldwin. I have met Miss Mason, and----" "And Miss Mason told you," interposed Arnold. "No. Mr. Tracey, informed by Miss Baldwin, told me. And it struck me as strange," added Bocaros, in rather a venomous tone, "that you should be engaged to the girl in whose house Flora was murdered." "It belongs to her brother-in-law," said Calvert coldly. "Do you mean to hint, professor, that I know anything about this crime?" "No," interposed Jasher, making a sign to Bocaros to hold his tongue, "he doesn't mean anything of the sort. Merely a coincidence, Mr. Calvert, such as will occur in real life." "Of course." Bocaros nodded and spoke with less significance. "I mean that it is merely a coincidence." Calvert looked from one to the other suspiciously, but set a mask on his face so that they should not guess what was passing in his mind. "We may as well understand one another," he said coolly. "If you, professor, or you, Mr. Jasher, are under the impression that I have anything to do with this crime--and you may think so from the fact that being notoriously hard up and notoriously anxious to marry Miss Mason I wanted this money--you are quite mistaken. I am engaged at the Frivolity Theatre from seven till close on midnight every night. I can prove what the law calls an _alibi_, and if you will apply to the stage manager of the theatre, you may convince yourself of the fact." "My dear sir," said Jasher deprecatingly, since Calvert was now his employer, "no one suspects you." "I thought from what Bocaros hinted----" "No! no! I said it was merely a coincidence," said the professor quickly. "The very fact that you are willing to employ Jasher, and offer so large a reward, proclaims your innocence." "I have no need to resort to such things," said Calvert angrily. "I only learned that the dead woman was my cousin from the fact of the White Room----" "But how did that lead to your identification of Flora with the dead woman?" asked Bocaros shrewdly. Arnold seemed confused. "I saw in the paper that the White Room had been remarked by a man called Webb, who had communicated with the police. It was then found by Inspector Derrick that Mrs. Brand had been missing. I fancied that she might be the unknown woman. I was informed that this was the truth by Merry, who has communicated with the police. I did not see the body or I would have been able to identify it. But Derrick found a portrait of my cousin, and says it is that of the dead woman."