The trio soon arrived at Kitty's house, and Ezra was just about to ring the front-door bell, when suddenly Naball touched his arm to stop him.

"Hist!" he said in a quick whisper; "listen."

A woman's voice, talking in a high key, and then the deep tones of a man's voice, like the growl of an angry beast.

"What did I tell you?" whispered Naball again. "Villiers and Caprice, both in the drawing-room; wait a moment, count twenty, and then ring the bell."

He stepped round the corner of the porch, stepped stealthily on to the verandah, and then stole softly towards one of the French windows in order to listen. He was correct in his surmise; the two speakers were Kitty Marchurst and Randolph Villiers.

"You'd better give me what I ask," growled Villiers in a threatening tone, "or I'll go straight and tell how you were at Lazarus's on the night of the murder."

"Perhaps you'll tell I killed him?" said Caprice, with a sneer.

"Perhaps I will," retorted Villiers; "there's no knowing."

"There's this much knowing," said Kitty deliberately, "that I won't give you a single penny. If I am called on to explain my movements, I can't do so; but it will be the worse for you, it will place--"

At this moment the bell rang, and Caprice started in alarm.

"Hush," she cried, advancing towards Villiers; "come to me again. I must not be seen talking with you here. Go away--not by the door," she said, with an angry stamp of her foot as Villiers went towards the door; "by the window--no one will see you."

Villiers moved towards the French window, opened it, and was just about to step out when Naball stepped forward.

"I'm afraid some one will," he said serenely, pushing Villiers back into the room, and closing the window.

"Naball!" cried Kitty and Villiers in a breath.

"Exactly," replied that gentleman, taking a chair. "I've come to have a talk with you both."

"How dare you force your way into my house?" cried Kitty angrily, while Villiers stood looking sullenly at the detective.

"It's about the diamond robbery," went on Naball, as if he never heard her.

"Leave the house," she cried, stamping her foot.

"And about the murder," he finished off, looking from one to the other.

Kitty glanced at Villiers, who looked at her with a scowl, and sank into a chair. Just as he did so, the drawing-room door opened, and Eugénie entered, followed by Ezra Lazarus.

"I don't understand the meaning of all this," said Caprice, with a sneer; "but you seem to have a good idea of dramatic effect."

"Perhaps so," replied Naball lazily. Kitty shrugged her shoulders and turned to Eugénie.

"Perhaps you can explain all this, Miss Rainsford?" she said coolly.

"Yes," answered Eugénie slowly; "it's about Mr. Stewart. You know he has been arrested for this murder?"

"Know," repeated Kitty impatiently, "of course, I know. I'm sure I ought to--morn, noon and night I've heard nothing else. I don't know how it will affect the piece, I'm sure."

"Never mind the piece," said Ezra, a trifle sternly. "I don't mind that, as long as I save my friend."

"I hope you will," said Caprice heartily. "I am certain he never committed the crime. What do you say?" turning to the detective.

"I'm beginning to be of your opinion," replied Naball candidly. "I did think him guilty once," fixing his eyes on Villiers, "but now I don't."

"What about the knife I gave you?" asked Villiers abruptly.

"Ah!" said Naball musingly, "what, indeed."

"I found it on the scene of the crime," said Villiers in a defiant manner.

"So you said."

"Don't you believe me?"

"Humph!"

At this ambiguous murmur Villiers gave a savage growl, and would have replied, but Kitty stopped him by waving her hand.

"It's no good talking like this," she said quickly. "There is some reason for you all coming here; what is it?"

"I'll tell you," said Naball in a sharp official tone. "Do you remember the diamond robbery at this place? Well, those diamonds were sold to old Lazarus, and he sent them to Amsterdam for sale. The person who stole those diamonds thought they were still in the safe of Jacob Lazarus; and the person who stole those diamonds murdered Jacob Lazarus to recover them."

He finished triumphantly, and then waited to see what effect his accusation would have on Kitty. To his astonishment, however, she never moved a muscle of her face, but asked calmly,--

"And who is the thief and the murderer?"

"That's what I want to find out."

"Naturally; but why come to me?"

"Because, you know."

"I!" she cried, rising to her feet in anger. "I know nothing."

"Yes, you do, and so does Villiers there," persisted Naball.

Villiers glanced strangely at Kitty, and growled sullenly.

"Now, look here Miss Marchurst," said Naball rapidly, "it's no use beating ............