On reaching the street, they crossed Ludgate Circus, and directed their steps towards Hatton Garden by way of St. Bride Street.

A few minutes later, they emerged in that portion of Holborn which is graced by the mounted statue of a dead German prince acknowledging his lifelong obligations to British hospitality by raising his plumed hat to the London City & Midland Bank on the Viaduct corner. Hatton Garden, as every Londoner knows, begins on the other side of this improving spectacle—a short broad street which disdains to indicate by external opulence the wealth hidden within its walls, though, to an eye practised in London ways, there is a comforting suggestion of prosperity in its wide flagged pavements, comfortable brick buildings, and Jewish names which appear in gilt lettering on plate-glass windows.

Colwyn walked quickly along, glancing at the displayed names. He had almost reached the Clerkenwell end of the Garden when his eye was caught by the name of "Austin Wendover, Dealer in Oriental Stones," gleaming in white letters on the blackboard indicator of a set of offices hived in a building on the corner of a side street. It was the name of the man he was searching for. He turned into the passage, and mounted the stairs. Caldew followed him.

On the landing of the first floor another and smaller board gave the names of those tenants whose offices were at the back of the building. Mr. Wendover's was amongst them, and a pointing hand opposite it revealed that he conducted his business at the end of a long passage with a bend in the middle. When this passage was traversed, Mr. Wendover's name was once more seen, this time on a door, with a notice underneath inviting the visitor to enter without knocking.

Within, a young Jew with a sensual face was busily writing at a desk in the corner, with his back to the door. He ceased and turned around at the sound of the opening door, and, thrusting his fountain pen behind an ear already burdened with a cigarette, waited to be informed what the visitors wanted.

"Is Mr. Wendover in?" Colwyn inquired.

"Yes, he is. What name, please?" The young Jew scrambled down from his stool preparatory to carrying a message.

In answer Colwyn tendered Musard's card of introduction. The young Jew scanned it, shot an appraising glance at the two detectives, and vanished into an inner room. He reappeared swiftly in the doorway, and beckoned them to enter.

The inner room was furnished with leather chairs, a good carpet, and a large walnut table. Mining maps and framed photographs of famous diamonds hung on the walls, but there was nothing about the man seated at the table to suggest association with precious stones except the gleam of his small grey eyes, which were as hard and glistening as the specimen gems in the showcase at his elbow. His face was long, thin and yellow, of a bilious appearance. His gaunt frame was clothed in black, and his low white collar ended in front in two linen tags, fastened with a penny bone stud instead of the diamond which might have been expected. This device, besides dispensing with a necktie, revealed the base of a long scraggy neck, with a tuft of grey hair pushing its way up from below and falling over the interstice of the collar, matching a similar tuft which dangled pendulously from the diamond merchant's nether lip. Altogether, as Mr. Austin Wendover sat at his table with his long yellow hands clasped in front of him waiting for his visitors to announce their business, he looked not unlike a Methodist pastor about to say grace, or a Garden City apostle of culture for the masses preparing to receive a vote of thanks for a lecture on English prose at a workers' mutual improvement society. Even his name suggested, to the serious mind, the compiler of an anthology of British war poets or the writer of a book of Nature studies, rather than the material wealth, female folly, late suppers, greenrooms, frivolity and immorality brought before a vivid imagination by the mere mention of the word diamonds.

"My name is Colwyn; my friend is Detective Caldew, of Scotland Yard," said Colwyn, in response to Mr. Wendover's glance of interrogation. "We are in search of a little information, which we trust you will give us."

"That depends upon what ye want to know." This reply, delivered in an abrupt and uncouth manner, suggested that the diamond merchant's disposition was anything but a cut and polished one.

"Quite so. You have heard of the Heredith murder, I presume."

The diamond merchant nodded his head without speaking, and waited to hear more.

"The Heredith necklace of pink pearls was stolen from Mrs. Heredith's room on the night that she was murdered, and we are endeavouring to trace it."

"And what has that got to do with me?"

"I have reason to think that the necklace may have been offered or sold in Hatton Garden. It may have been submitted to you."

"What d'ye mean by coming to me with such a question? What does Mr. Musard mean by sending ye here? Does he think I've turned receiver of stolen property at my time of life? I'm surprised at him."

"My dear Mr. Wendover, Mr. Musard had no such thought in his mind. We simply come to you for information. Mr. Musard gave me your address as a reputable dealer of stones who would be likely to know if this necklace had been offered for sale in Hatton Garden."

"Well, it has not been offered to me. I've handled no pearls for twelve months."

"Would you know the Heredith necklace if it were offered to you?"

"I would not, and I've already told ye it was not offered to me."

Colwyn was nonplussed and disappointed, but the recollection of Nepcote's furtive glance and hasty concealment of the diamond merchant's card on the previous night prompted him to a further effort.

"It is possible the necklace may have been broken up and the stones offered separately," he said. "The clasp contained a large and valuable blue diamond."

"I tell ye I know nothing about it. I very rarely buy from private persons. It's not my way of doing business."

"We have reason to suspect that the necklace was offered for sale by a young military officer, tall and good looking, with blue eyes and brown hair, slightly tinged with grey at the temples."

"That description would apply to thousands of young officers. They're a harum-scarum lot, and dissipation soon turns a man's hair grey. I have had some of them here, trying to sell family jewels for money to throw away on painted women. There was one who called some days ago in a half-intoxicated condition. He clapped me on the back as impudent as you please, and calling me a thing—a dear old thing, which is one of their slang phrases—asked me what he could screw out of me for a good diamond. I sent him and his diamond off with a flea in the ear." Mr. Wendover's gummy lips curved in a grim smile at the recollection.

"Can you describe him more particularly?" asked Colwyn, with sudden interest.

"I paid no particular attention to him, and I wouldn't know him again if he were to walk in the door. It was almost dark when he came, and my eyes are not young. But he was not the man ye're after. It was days before the murder."

"Did he give you his name?"

"He did not, and I wouldn't tell ye if he did. What's it to do with the object of your visit? Ye're a persistent sort of young fellow, but I'm not going to let ye hold a general fishing inquiry into my business. There are two kinds of foolish folk in this world. Those who babble of their affairs to their womenfolk, and those who babble of them to strangers. I have no womenfolk, thank God! so I cannot talk to the futile creatures."

"Then I shall not ask you to break the other half of your maxim on my account," said Colwyn, rising with a smile.

"It would be no good if ye did," responded Mr. Wendover, with a reciprocatory grin which displayed two yellow fangs like the teeth of a walrus. "My business conscience is already pricking me for having said so much. He that holds his own counsel gives away nothing—except that he holds his counsel. Ye might do worse than lay that to your heart, Mr. Colwyn, in your walk through life. There's fifty years' experience behind it. Good-bye to ye, Mr. Colwyn, and ye, young man. I wish ye both luck in your search, but my advice is, try the pawn-shops." At the pressure of his thumb on the table the young Jew appeared from the next room, as if summoned by a magic wand, to let the visitors out.

"That's a queer old bird," said Caldew, as they walked away. "Do you think he has told us the truth?"

Colwyn did not reply. He was thinking rapidly, and wondering whether by any possibility he had made a mistake. But once more there flashed into his mind, like an image projected on a screen, the little scene which he alone had witnessed at the flat on the previous evening—the fluttering cards, the quick, unconscious gesture of concealment, and the startled glance which so plainly reflected the dread of discovery. No! there was no mistake there, but the explanation lay deeper.

They had reached the angle of the narrow passage which led to the front outlet of the offices. A small window was fixed at the dark turn of the long dark corridor to admit light. Colwyn chanced to glance through this window as he reached it, and his quick eye took in the figure of a man standing motionless in a narrow alley of the side street below. He was almost concealed behind an archway, but it was apparent to the detective that he was watching the corner building. As Colywn looked at him he slightly changed his position and his face came into view. With a quick imperative gesture to his companion, Colwyn ran swiftly along the remainder of the corridor and down the flight of stairs into Hatton Garden.

Caldew followed more slowly, puzzled by the other's strange action. When he reached the doorway Colwyn was nowhere to be seen, so he waited in the entrance. After the lapse of a few minutes he saw Colwyn returning from the direction of Clerkenwell.

"He has got away," he said, as he reached Caldew. His voice was a little breathless, as though with running.

"He? Who?"

Colwyn drew him into the empty entrance hall before he answered:

"Nepcote. He was watching outside. I saw him through the upstairs window. He either followed us here or has been waiting to see if we came. I should have foreseen this."

A flicker of unusual agitation on Colwyn's calm face increased Caldew's mental confusion.

"I don't understand," he stammered. "He—Nepcote—why should he be watching us?"

"Because he penetrated the truth last night. He knew he was in danger."

"But why should he follow us here?"

"He accidentally dropped some cards from his pocket-book when giving Merrington an address at his flat last night, and one of them was Wendover's business card. Merrington did not see it—it would have conveyed nothing to him if he had—but I did. Nepcote knew that I saw it, and must have realized that I suspected him. He has been watching my rooms and followed us here, or he has been hanging around this place to see if I called on Wendover."

"Even now I do not see the connection. If Wendover told us the truth, Nepcote has not been to him with the necklace. Then what did it matter to Nepcote whether you came here or not?"

"Nepcote may have been the man who offered the diamond to Wendover."

"That is impossible. Wendover says that man called some days before the murder."

"Still, it may have been Nepcote."

"That goes beyond me," said Caldew, with a puzzled look. "What are you implying?"

"Nothing at present. Every step in this case convinces me that we are faced with a very deep mystery. It isn't worth while to hazard a guess, because guessing is always unsatisfactory."

"Perhaps we had better try and get a little more out of Wendover," said Caldew.

"That would be merely waste of time. He has not got the necklace, and he is unable to describe the man who offered him the diamond. I believe now that it was Nepcote, but that doesn't matter, one way or another. It is far more important to know that he came here to-day to watch for us. That implies that he had reason to fear investigations about the necklace. The inference to be drawn is that Nepcote is responsible for the disappearance of the necklace, and is, therefore, deeply implicated in the murder."

"Perhaps it was not Nepcote that you saw?" suggested Caldew. He felt that the remark was a feeble one, but he was bewildered by the sudden turn of events, and in a frame of mind which clutches at straws.

"Put that doubt out of your mind," said Colwyn. "I saw his face distinctly. He had disappeared by the time I got down. The alley where he was standing commanded a view of the entrance of this building. I ascertained that by standing in the same spot. His flight is another proof—though that was not needed—of his guilty knowledge and complicity in this murder. Why should he run away? According to his own story last night he had nothing to fear. But now, by his own actions, he has brought the utmost suspicion on himself."

"I suppose it is no use searching about here for him?" remarked Caldew, glancing gloomily out of the doorway.

"Not in the least. The neighbourhood is a warren of alleys and side streets from here to Grays Inn Road."

"Then I shall go up to his flat at once," said Caldew. "He has not had time to go back."

"He will not return to his flat. We have seen the last of him until we catch him. He has had two warnings, and he is not likely to be guilty of the folly of waiting to see whether lightning strikes thrice in the same spot. He will get away for good, this time, if he can. Nevertheless it is worth while going to the flat. We may pick up some points there." Colwyn uttered these last words in a lower tone at the sight of two office girls descending the staircase with much chatter and laughter.

"Let us go then."

They travelled by 'bus from Grays Inn Road as far as Oxford Circus, and walked along a number of quiet secluded streets—the backwaters of the West End—in order to reach Sherryman Street from the lower end, which, with a true sense of the fitness of things, was called Sherryman Street Approach. If the Approach had not been within a stone's throw of Sherryman Square it might have been called a slum. It had tenement houses with swarms of squalid children playing in the open doorways, its shops offered East End food—mussels and whelks, "two-eyed steaks," reeking fish-and-chips, and horsemeat for the cheap foreign element. There were several public-houses with groups of women outside drinking and gossiping, all wearing the black shawls which are as emblematic of the lower class London woman as a chasuble to a priest, or a blue tattooed upper lip to a high-caste Maori beauty. A costermonger hawked frozen rabbits from a donkey-cart, with a pallid woman following behind to drive away the mangy cats which quarrelled in the road for the oozing blood which dripped from the cart's tail. An Italian woman, swarthy, squat, and intolerably dirty, ground out the "Marseillaise" from a barrel-organ with a shivering monkey capering atop, waving a small Union Jack, and impatiently rattling a tin can for coppers.

To turn from this squalid quarter into Sherryman Street was to pass from the east to the west end of London at a step. It was as though an invisible line of demarcation had been drawn between the lower and upper portion of the street, and held inviolate by the residents of each portion. There were no public houses or fish-shops in Sherryman Street; no organ-grinders, costermongers, unclean children, or women in black shawls. It had quiet, seclusion, clean pavements, polished doorknockers, and white curtains at the windows of its well-kept houses, which grew in dignity to the semblance of town mansions at the Square end.

Number 10 showed a blank closed stone exterior to the passer-by, like an old grey secretive face. As they approached it Colwyn, with a slight movement of his head, drew his companion's attention to the upper windows which belonged to Nepcote's flat. The blinds were down.

"It looks as if Nepcote left last night," he said.

The sight of the drawn blinds, like yellow eyelids in the grey face, awakened some secret irritation in Caldew's breast, and with it the realization of his powers as an officer of Scotland Yard.

"I shall force a way in and see," he angrily declared.

"Better get a key from the housekeeper," suggested Colwyn. "The women who look after these bachelor flats always have duplicate keys. But the front door is ajar. Let us go upstairs first."

They ascended the stairs to the flat, and the first thing they noticed was a Yale key in the keyhole of the door.

"A sign of mental upset," commented Colwyn. "At such moments people forget the little things."

They opened the door and entered. The front room was much as Colwyn had seen it the previous night. The flowers drooped in their bowl; the chorus girls smirked in their silver settings; the framed racehorses and their stolid trainers looked woodenly down from the pink walls.

"Nepcote does not seem to have taken anything away with him," remarked Caldew, looking into the bedroom. "The wardrobe is full of his uniforms, but the bed has not been occupied."

"Here is the proof that he has fled," said Colwyn, flinging back the lid of a desk which stood in the sitting-room. It was filled to the brim with a mass of torn papers.

"Anything compromising?" asked Caldew, eagerly approaching to look at the litter.

"No; only bills and invitations. Any dangerous letters have been burnt there." He pointed to the grate, which was heaped with blackened fragments. "He's made a good job of it too," he added, as he went to the fireplace and bent over it. "There's not the slightest chance of deciphering a line. But it would be as well to search his clothes. He may have forgotten some letters in the pockets."

Caldew took the hint, and disappeared into the inner room, leaving Colwyn examining the contents of the grate. He returned in a few minutes to say that he had found nothing in the clothes except a few Treasury notes and some loose silver in a trousers' pocket.

"That looks as if he had bolted in such a hurry that he forgot to take his change with him," said Colwyn. "It is another interesting revelation of his state of mind, because there is very little doubt that he returned to the flat this morning after leaving it last night."

"How do you arrive at that conclusion?"

"By the burnt letters in the grate. They are still warm. He was in such a state of fear that he dared not sleep in the flat last night, but he returned this morning to burn his letters and change into civilian clothes. Then he rushed away again in such a hurry that he forgot his money. There is nothing more to be seen here. We had better make a few inquiries of the housekeeper as we go downstairs."

They walked out, and Caldew locked the door behind him and placed the key in his pocket. When they reached the entrance hall Colwyn paused outside the door of the recess where the housekeeper lurked, like an octopus in a pool. At Colwyn's knock a white face, topped by a white cap, came into view through the narrow slit in the curtained glass half of the door, and swam towards them in the interior gloom after the manner of the head of a materialized ghost in a spirit medium's parlour. The door opened, and the apparition appeared in the flesh, looking at them with stony eyes. Caldew undertook the conversation:

"Did Captain Nepcote sleep here last night?" he curtly asked.

"I don't know."

"Well, has he been here this morning?"

"I don't know." The tone of the second reply was even more expressionless than the first, if that were possible.

"It's your business to know," said Caldew angrily.

"It is not my business to discuss Captain Nepcote's private affairs with strangers." The woman turned back into her room without another word, closing the door behind her.

"D—n her!" muttered Caldew, in intense exasperation.

"These ancient females learn the wisdom of controlling their natural garrulity when placed in charge of bachelors' flats," said Colwyn with a laugh. "We will get nothing out of her if we stay here all day, so we had better go."

"I am going straight back to Scotland Yard," Caldew announced with sudden decision when they reached the pavement. "I must tell Merrington all about this morning's work, and the sooner the better. We must have the flat watched. Perhaps Nepcote may return."

"He will not return," said Colwyn. "He knows that we are after him, and that the flat will be watched. But it is a good idea not to let him have too long a start. Come, let us see if we can find a taxi, and I will drop you at Scotland Yard."

They walked along to Sherryman Square, and esteemed themselves fortunate in picking up a cruising taxi-cab with a driver sufficiently complaisant to drive them in the direction they wished to go.