The silence that followed on this extraordinary exclamation was suddenly broken: the mortuary keeper, who had been advancing towards a door at the side of the room, dropped a bunch of keys. The strange metallic sound of their falling roused Ayscough, who had started aside, and was staring, open-mouthed, at Mirandolet's waving hands. He caught the doctor by the arm.

"What on earth do you mean?" he growled. "Speak man--what is it?"

Mirandolet suddenly laughed.

"What is it?" he exclaimed. "Precisely what I said, in plain language! That fellow has, of course, gone off with the diamond--worth eighty thousand pounds! Your card!--Oh, man, man, whatever have you been doing? Be quick!--who is this Japanese?--how came he by your card? Quick, I say! --if you want to be after him!"

"Hanged if I know what this means!" muttered Ayscough. "As to who he is-- if he's the fellow I gave a card to, he's a young Japanese medical student, one Yada, that was a friend of those Chinese--I called on him tonight, with Rubinstein, to see if we could pick up a bit of information. Of course, I sent in my professional card to him. But--we saw him set off to the East End!"

"Bah!" laughed Mirandolet. "He has--what you call done you brown, my friend! He came--here! And he has got away--got a good start--with that diamond in his pocket!"

"What the devil do you mean by that?" said Ayscough, hotly. "Diamond! Diamond! Where should he find the diamond--here? In a deadhouse? What are you talking about?"

Mirandolet laughed again, and giving the detective a look that was very like one of pitying contempt, turned to the amazed mortuary keeper.

"Show us that dead man!" he said.

The mortuary keeper, who had allowed his keys to lie on the floor during this strange scene, picked them up, and selecting one, opened, and threw back the door by which he was standing. He turned on the light in the mortuary chamber, and Mirandolet strode in, with Ayscough, sullen and wondering, at his heels.

Chen Li lay where the detective had last seen him, still and rigid, the sheet drawn carefully over his yellow face. Without a word Mirandolet drew that sheet aside, and motioning his companion to draw nearer, pointed to a skull-cap of thin blue silk which fitted over the Chinaman's head.

"You see that!" he whispered. "You know what's beneath it!--something that no true Chinaman ever parts with, even if he does come to Europe, and does wear English dress and English headgear--his pigtail! Look here!"

He quietly moved the skull-cap, and showed the two astonished men a carefully-coiled mass of black hair, wound round and round the back of the head. And into it he slipped his own long, thin fingers--to draw them out again with an exclamation which indicated satisfaction with his own convictions.

"Just as I said," he remarked. "Gone! Mr. Detective--that's where Chen Li hid the diamond--and that Japanese man has got it. And now--you'd better be after him--half-an-hour's start to him is as good as a week's would be to you."

He drew the sheet over the dead face and strode out, and Ayscough followed, angry, mystified, and by no means convinced.

"Look here!" he said, as they reached the ante-room; "that's all very well, Dr. Mirandolet, but it's only supposition on your part!"

"Supposition that you'll find to be absolute truth, my good friend!" retorted Mirandolet, calmly. "I know the Chinese--better than you think. As soon as I heard of this affair tonight, I came to you to put you up to the Chinese trick of secreting things of value in their pigtails--it did not occur to me that the diamond might be there in this case, but I thought you would probably find something. But when we reached this mortuary, and I heard that a Japanese had been here, presenting your card when he had no business to present it, I guessed immediately what had happened--and now that you tell me that you told him all about this affair, well--I am certain of my assertion. Mr. Detective--go after the diamond!"

He turned as if to leave the place, and Ayscough followed.

"He mayn't been after the diamond at all!" he said, still resentful and incredulous. "Is it very likely he'd think it to be in that dead chap's pigtail when the other man's missing? It's Chang that's got that diamond-- not Chen."

"All right, my friend!" replied Mirandolet. "Your wisdom is superior to mine, no doubt. So--I wish you good-night!"

He strode out of the place and turned sharply up the street, and Ayscough, after a growl or two, went back to the mortuary keeper.

"How long was that Jap in there?" he asked, nodding at the death chamber.

"Not a minute, Mr. Ayscough!" replied the man. "In and out again, as you might say."

"Did he say anything when he came out?" enquired the detective.

"He did--two words," answered the keeper. "He said, 'That's he!' and walked straight out, and into his car."

"And when he came he told you I'd sent him?" demanded Ayscough.

"Just that--and showed me your card," assented the man. "Of course, I'd no reason to doubt his word."

"Look here, George!" said Ayscough, "you keep this to yourself! Don't say anything to any of our folks if they come in. I don't half believe what that doctor said just now--but I'll make an enquiry or two. Mum's the word, meanwhile. You understand, George?"

George answered that he understood very well, and Ayscough presently left him. Outside, in the light of the lamp set over the entrance to the mortuary, he pulled out his watch. Twelve o'clock--midnight. And somewhere, that cursed young Jap was fleeing away through the London streets--having cheated him, Ayscough, at his own game!

He had already reckoned things up in connection with Yada. Yada had been having him--even as Melky Rubinstein had suspected and suggested--all through that conversation at Gower Street. Probably, Yada, from his window in the drawing-room floor of his lodging-house, had watched him and Melky slip across the street and hide behind the hoarding opposite. And then Yada had gone out, knowing he was to be followed, and had tricked them beautifully, getting into an underground train going east, and, in all certainty, getting out again at the next station, chartering a cab, and returning west--with Ayscough's card in his pocket.

But Ayscough knew one useful thing--he had memorized the letters and numbers of the taxi-cab in which Yada had sped by him and Mirandolet, L.C. 2571--he had kept repeating that over and over. Now he took out his note- book and jotted it down--and that done he set off to the police-station, intent first of all on getting in touch with New Scotland Yard by means of the telephone.

Ayscough, like most men of his calling in London, had a considerable amount of general knowledge of things and affairs, and he summoned it to his aid in this instance. He knew that if the Japanese really had become possessed of the orange and yellow diamond (of which supposition, in spite of Mirandolet's positive convictions, he was very sceptical) he would most certainly make for escape. He would be off to the Continent, hot foot. Now, Ayscough had a good acquaintance with the Continental train services --some hours must elapse before Yada could possibly get a train for Dover, or Folkstone, or Newhaven, or the shortest way across, or to any other ports such as Harwich or Southampton, by a longer route. Obviously, the first thing to do was to have the stations at Victoria, and Charing Cross, and Holborn Viaduct, and London Bridge carefully watched for Yada. And for two weary hours in the middle of the night he was continuously at work on the telephone, giving instructions and descriptions, and making arrangements to spread a net out of which the supposed fugitive could not escape.

And when all that was at last satisfactorily arranged, Ayscough was conscious that it might be for nothing. He might be on a wrong track altogether--due to the suspicions and assertions of that queer man, Mirandolet. There might be some mystery--in Ayscough's opinion there always was mystery wherever Chinese or Japanese or Hindus were concerned. Yada might have some good reason for wishing to see Chen Li's dead body, and have taken advantage of the detective's card to visit it. This extraordinary conduct might be explained. But meanwhile Ayscough could not afford to neglect a chance, and tired as he was, he set out to find the driver of the taxicab whose number he had carefully set down in his notebook.

There was little difficulty in this stage of the proceedings; it was merely a question of time, of visiting a central office and finding the man's name and address. By six o'clock in the morning Ayscough was at a small house in a shabby street in Kentish Town, interviewing a woman who had just risen to light her fire, and was surlily averse to calling up a husband, who, she said, had not been in bed until nearly four. She was not any more pleased when Ayscough informed her of his professional status-- but the man was fetched down.

"You drove a foreigner--a Japanese--to the mortuary in Paddington last night?" said Ayscough, plunging straight into business, after telling the man who he was. "I saw him--just a glimpse of him--in your cab, and I took your number. Now, where did you first pick him up?"

"Outside the Underground, at King's Cross," replied the driver promptly.

This was precisely what Ayscough had expected; so far, so good; his own prescience was proving sure.

"Anything wrong, mister?" asked the driver.

"There may be," said Ayscough. "Well--you picked him up there, and drove him straight to the mortuary?"

"No--I didn't," said the man. "We made a call first. Euston. He went in there, and, I should say, went to the left luggage office, 'cause he came back again with a small suit-case--just a little 'un. Then we went on to that mortuary."

Euston! A small suit-case! More facts--Ayscough made notes of them.

"Well," he said, "and when you drove away from the mortuary, where did you go then?"

"Oxford Circus," answered the driver, "set him down--his orders--right opposite the Tube Station--t'other side of the street."

"Did you see which way he went--then?" enquired Ayscough.

"I did. Straight along Oxford Street--Tottenham Court Road way," said the driver, "carrying his suitcase--which it was, as I say, on'y a little 'un --and walking very fast. Last I see of him was that, guv'nor."

Ayscough went away and got back to more pretentious regions. He was dead tired and weary with his night's work, and glad to drop in at an early- opened coffee-shop and get some breakfast. While he ate and drank a boy came in with the first editions of the newspapers. Ayscough picked one up --and immediately saw staring headlines:--

THE PADDINGTON MYSTERIES.
NEW AND STARTLING FEATURES.
DIAMOND WORTH L80,000 BEING LOOKED FOR
MURDER IN MAIDA VALE

Ayscough laid down the paper and smiled. Levendale--if not dead--could scarcely fail to see that!