Something in his tone made Sidney look up. Gimblet was looking at him with a strange expression, and as their eyes met he turned away uneasily. For a minute Sidney stared at him wonderingly, and then an incredulous enlightenment stole over him.

“You can’t mean,” he said slowly, “that you imagine she had any knowledge of the attack on my aunt?”

Gimblet was silent; and his silence was more eloquent than words.

“But it is impossible,” cried Sidney, “that anyone out of a lunatic asylum should think such a thing. You don’t know her, Mr. Gimblet, she is the sweetest, dearest girl. The most unselfish, the most devoted, the loyalest girl in the world! How can you hint at it? Oh, I know it is your business to suspect people, but you go too far! I cannot hear a word against her.”

Gimblet turned and faced him.

“Be reasonable, Mr. Sidney,” he said, “and accept it as a fact that the young lady will be suspected. If she is innocent it will be better to try and clear her than to refuse to hear what there is to be said as to her possible complicity. I understand your feelings, but you must see that there is nothing to gain by disguising the truth. It is because I thought it possible that you might feel a keen interest in Miss Turner that I have told you I suspect her. I hope you may be able to help me to convince myself of her innocence, and surely the best way to do that is to try and get at the truth.”

“I will try and be reasonable, as you call it,” said Sidney, after a pause, “and I suppose by that you mean listening to your abominable accusations. Well, let’s hear your evidence, and if I can prevent myself from throttling you I will! More than that no man could say,” he added, with an attempt at a smile. “And I feel a beast even to allow you to speak of the thing.”

“I am extremely sorry to have to do it,” said Gimblet, “but no good ever came of shutting one’s eyes to facts, and it’s facts that make me suspect Miss Turner. In the first place, there is the fact that she stands to profit by Mrs. Vanderstein’s death to the tune of £30,000.”

“That applies to me, too, only more so,” interrupted Sidney.

“Yes, and I don’t think it of much importance,” admitted the detective. “I mention it as one of the points which is outside the region of speculation, and therefore not negligible. The second fact is that you were at your wits’ end for money.”