"It will be all right directly he comes back," Lenora whispered, laying her hand upon Quest's arm.

"If only some one would give me my jewels and let me go!" Mrs. Rheinholdt moaned.

The door opened and the Inspector reappeared. He was looking graver than ever.

"Quest," he announced, "your alibi is useless--in fact a little worse than useless. The operator at Number 10 has been found murdered at the back of his tower!"

Quest started.

"I ought not to have left him to those thugs," he murmured regretfully.

"There is no automobile of yours in the vicinity," the Inspector continued, "nor any news of it. I think it will be as well now, Quest, for this matter to take its obvious course. Will you, first of all, hand over her jewels to Mrs. Rheinholdt?"

Quest drew the keys of the safe from his pocket, crossed the room and swung open the safe door. For a moment afterwards he stood transfixed. His arm, half outstretched, remained motionless. Then he turned slowly around.

"The jewels have been stolen," he announced with unnatural calm.

Mrs. Rheinholdt pushed her way forward, wringing her hands.

"Stolen again?" she said. "Mr. Quest! Inspector!"

"They were there," Quest declared, "when I left the house this morning. It seems probable," he added, "that the same person who is responsible for this double tragedy has also taken the jewels."

The Inspector laid his hand heavily upon Quest's shoulder.

"It does seem as though that might be so," he a.s.sented grimly. "You will kindly consider yourself under arrest, Quest. Ladies and gentlemen, will you clear the room now, if you please? The ambulance I telephoned for is outside."

The Professor, who had been looking on as though dazed, suddenly intervened.

"Mr. French," he said earnestly, "I am convinced that you are making a great mistake. In arresting and taking away Mr. Quest, you are removing from us the one man who is likely to be able to clear up this mystery."

The Inspector pushed him gently on one side.

"You will excuse me, Professor," he said, "but this is no matter for argument. If Mr. Quest can clear himself, no one will be more glad than I."

Quest shrugged his shoulders.

"The Inspector will have his little joke," he observed drily. "It's all right, girls. Keep cool," he went on, as he saw the tears in Lenora's eyes. "Come round and see me in the Tombs, one of you."

"If I can be of any a.s.sistance," the Professor exclaimed, "I trust that you will not fail to call upon me, Mr. Quest. I repeat, Inspector," he added, "I am convinced that you are making a very grave mistake. Mrs.

Rheinholdt, you must let me take you home."

She gave him her arm.

"My jewels!" she sobbed. "Just as they had been recovered, too!"

"My dear lady," the Professor reminded her, with a faint air of reproach in his tone, "I think we must remember that we are in the presence of a graver tragedy than the loss of a few jewels."...

The ambulance men came and departed with their grim burden, the room on the ground floor was locked and sealed, and the house was soon empty except for the two girls. Towards three o'clock, Lenora went out and returned with a newspaper. She opened it out upon the table and they both pored over it.--

"WELL-KNOWN CRIMINOLOGIST ARRESTED FOR DOUBLE TRAGEDY!

"Sanford Quest, the famous New York criminologist, was arrested at noon to-day, charged with the murder of his valet, Ross Brown, and Miss Quigg, Salvation Army canva.s.ser. The crime seems to be mixed up in some mysterious fashion with others. John D.

Martin, of signal tower Number 10, offered by Quest as an alibi, was found dead behind his tower. Quest claimed that he travelled from the signal tower to New York on a freight train, leaving his automobile behind, but neither machine nor chauffeur have been discovered.

"Justice Thorpe has refused to consider bail."

"He's a guy, that Justice Thorpe, and so's the idiot who wrote this stuff!" Laura exclaimed, thrusting the paper away from her. "I guess the Professor was dead right when he told French he was locking up the one man who could clear up the whole show."

Lenora nodded thoughtfully.

"The Professor spoke up like a man," she agreed, "but, Laura, I want to ask you something. Did you notice his servant--that man Craig?"

"Can't say I did particularly," Laura admitted.

"Twice," Lenora continued, "I thought he was going to faint. I tell you he was scared the whole of the time."

"What are you getting at, kid?" Laura demanded.

"At Craig, if I can," Lenora replied, moving towards the telephone.

"Please give me the phototelesme. I am going to talk to the Professor."

Laura adjusted the mirror to the instrument and Lenora rang up. The Professor himself answered the call.

"Have you seen the three o'clock edition, Professor?" Lenora asked.

"I never read newspapers, young lady," the Professor replied.

"Let me tell you what they say about Mr. Quest!"

Lenora commenced a rambling account of what she had read in the newspaper.

All the time the eyes of the two girls were fixed upon the mirror. They could see the Professor seated in his chair with two huge volumes by his side, a pile of ma.n.u.script, and a pen in his hand. They could even catch the look of sympathy on his face as he listened attentively. Suddenly Lenora almost broke off. She gripped Laura by the arm. The door of the study had been opened slowly, and Craig, carrying a bundle, paused for a moment on the threshold. He glanced nervously towards the Professor, who seemed unaware of his entrance. Then he moved stealthily towards the fireplace, stooped down and committed something to the flames. The relief on his face, as he stood up, was obvious.

"All I can do for Mr. Quest, young lady, I will," the Professor promised.

"If you will forgive my saying so, you are a little over-excited just now.

Take my advice and rest for a short time. Call round and see me whenever you wish."

He laid the receiver down and the reflection on the mirror faded away.

Lenora started up and hastily put on her coat and hat, which were still lying on the chair.

"I am going right down to the Professor's," she announced.

"What do you think you can do there?" Laura asked.

"I am going to see if I can find out what that man burnt," she replied. "I will be back in an hour."

Laura walked with her as far as the street car, and very soon afterwards Lenora found herself knocking at the Professor's front door. Craig admitted her almost at once. For a moment he seemed to shiver as he recognised her. The weakness, however, was only momentary. He showed her into the study with grave deference. The Professor was still immersed in his work. He greeted her kindly, and with a little sigh laid down his pen.