"Did you ever see Mr. Errington, the gentleman so closely connected with the mysterious death on the Underground Railway?" asked the man in the corner as he placed one or two of his little snap-shot photos before Miss Polly Burton.

"There he is, to the very life. Fairly good-looking, a pleasant face enough, but ordinary, absolutely ordinary.

"It was this absence of any peculiarity which very nearly, but not quite, placed the halter round Mr. Errington's neck.

"But I am going too fast, and you will lose the thread.

"The public, of course, never heard how it actually came about that Mr. Errington, the wealthy bachelor of Albert Mansions, of the Grosvenor, and other young dandies' clubs, one fine day found himself before the magistrates at Bow Street, charged with being concerned in the death of Mary Beatrice Hazeldene, late of No. 19, Addison Row.

"I can assure you both press and public were literally flabbergasted. You see, Mr. Errington was a well-known and very popular member of a certain smart section of London society. He was a constant visitor at the opera, the racecourse, the Park, and the Carlton, he had a great many friends, and there was consequently quite a large attendance at the police court that morning.

"What had transpired was this:

"After the very scrappy bits of evidence which came to light at the inquest, two gentlemen bethought themselves that perhaps they had some duty to perform towards the State and the public generally. Accordingly they had come forward, offering to throw what light they could upon the mysterious affair on the Underground Railway.

"The police naturally felt that their information, such as it was, came rather late in the day, but as it proved of paramount importance, and the two gentlemen, moreover, were of undoubtedly good position in the world, they were thankful for what they could get, and acted accordingly; they accordingly brought Mr. Errington up before the magistrate on a charge of murder.

"The accused looked pale and worried when I first caught sight of him in the court that day, which was not to be wondered at, considering the terrible position in which he found himself.

"He had been arrested at Marseilles, where he was preparing to start for Colombo.

"I don't think he realized how terrible his position really was until later in the proceedings, when all the evidence relating to the arrest had been heard, and Emma Funnel had repeated her statement as to Mr. Errington's call at 19, Addison Row, in the morning, and Mrs. Hazeldene starting off for St. Paul's Churchyard at 3.30 in the afternoon.

"Mr. Hazeldene had nothing to add to the statements he had made at the coroner's inquest. He had last seen his wife alive on the morning of the fatal day. She had seemed very well and cheerful.

"I think every one present understood that he was trying to say as little as possible that could in any way couple his deceased wife's name with that of the accused.

"And yet, from the servant's evidence, it undoubtedly leaked out that Mrs. Hazeldene, who was young, pretty, and evidently fond of admiration, had once or twice annoyed her husband by her somewhat open, yet perfectly innocent, flirtation with Mr. Errington.

"I think every one was most agreeably impressed by the widower's moderate and dignified attitude. You will see his photo there, among this bundle. That is just how he appeared in court. In deep black, of course, but without any sign of ostentation in his mourning. He had allowed his beard to grow lately, and wore it closely cut in a point.

"After his evidence, the sensation of the day occurred. A tall, dark-haired man, with the word 'City' written metaphorically all over him, had kissed the book, and was waiting to tell the truth, and nothing but the truth.

"He gave his name as Andrew Campbell, head of the firm of Campbell & Co., brokers, of Throgmorton Street.

"In the afternoon of March 18th Mr. Campbell, travelling on the Underground Railway, had noticed a very pretty woman in the same carriage as himself. She had asked him if she was in the right train for Aldersgate. Mr. Campbell replied in the affirmative, and then buried himself in the Stock Exchange quotations of his evening paper.

"At Gower Street, a gentleman in a tweed suit and bowler hat got into the carriage, and took a seat opposite the lady.

"She seemed very much astonished at seeing him, but Mr. Andrew Campbell did not recollect the exact words she said.

"The two talked to one another a good deal, and certainly the lady appeared animated and cheerful. Witness took no notice of them; he was very much engrossed in some calculations, and finally got out at Farringdon Street. He noticed that the man in the tweed suit also got out close behind him, having shaken hands with the lady, and said in a pleasant way: 'Au revoir! Don't be late to-night.' Mr. Campbell did not hear the lady's reply, and soon lost sight of the man in the crowd.

"Every one was on tenter-hooks, and eagerly waiting for the palpitating moment when witness would describe and identify the man who last had seen and spoken to the unfortunate woman, within five minutes probably of her strange and unaccountable death.

"Personally I knew what was coming before the Scotch stockbroker spoke.

"I could have jotted down the graphic and lifelike description he would give of a probable murderer. It would have fitted equally well the man who sat and had luncheon at this table just now; it would certainly have described five out of every ten young Englishmen you know.

"The individual was of medium height, he wore a moustache which was not very fair nor yet very dark, his hair was between colours. He wore a bowler hat, and a tweed suit — and — and — that was all — Mr. Campbell might perhaps know him again, but then again, he might not — he was not paying much attention — the gentleman was sitting on the same side of the carriage as himself — and he had his hat on all the time. He himself was busy with his newspaper — yes — he might know him again — but he really could not say.

"Mr. Andrew Campbell's evidence was not worth very much, you will say. No, it was not in itself, and would not have justified any arrest were it not for the additional statements made by Mr. James Verner, manager of Messrs. Rodney & Co., colour printers.

"Mr. Verner is a personal friend of Mr. Andrew Campbell, and it appears that at Farringdon Street, where he was waiting for his train, he saw Mr. Campbell get out of a first-class railway carriage. Mr. Verner spoke to him for a second, and then, just as the train was moving off, he stepped into the same compartment which had just been vacated by the stockbroker and the man in the tweed suit. He vaguely recollects a lady sitting in the opposite corner to his own, with her face turned away from him, apparently asleep, but he paid no special attention to her. He was like nearly all business men when they are travelling — engrossed in his paper. Presently a special quotation interested him; he wished to make a note of it, took out a pencil from his waistcoat pocket, and seeing a clean piece of paste-board on the floor, he picked it up, and scribbled on it the memorandum, which he wished to keep. He then slipped the card into his pocket-book.

"'It was only two or three days later,' added Mr. Verner in the midst of breathless silence, 'that I had occasion to refer to these same notes again.

"'In the meanwhile the papers had been full of the mysterious death on the Underground Railway, and the names of those connected with it were pretty familiar to me. It was, therefore, with much astonishment that on looking at the paste-board which I had casually picked up in the railway carriage I saw the name on it, "Frank Errington."'

"There was no doubt that the sensation in court was almost unprecedented. Never since the days of the Fenchurch Street mystery, and the trial of Smethurst, had I seen so much excitement. Mind you, I was not excited — I knew by now every detail of that crime as if I had committed it myself. In fact, I could not have done it better, although I have been a student of crime for many years now. Many people there — his friends, mostly — believed that Errington was doomed. I think he thought so, too, for I could see that his face was terribly white, and he now and then passed his tongue over his lips, as if they were parched.

"You see he was in the awful dilemma — a perfectly natural one, by the way — of being absolutely incapable of proving an alibi. The crime — if crime there was — had been committed three weeks ago. A man about town like Mr. Frank Errington might remember that he spent certain hours of a special afternoon at his club, or in the Park, but it is very doubtful in nine cases out of ten if he can find a friend who could positively swear as to having seen him there. No! no! Mr. Errington was in a tight corner, and he knew it. You see, there were — besides the evidence — two or three circumstances which did not improve matters for him. His hobby in the direction of toxicology, to begin with. The police had found in his room every description of poisonous substances, including prussic acid.

"Then, again, that journey to Marseilles, the start for Colombo, was, though perfectly innocent, a very unfortunate one. Mr. Errington had gone on an aimless voyage, but the public thought that he had fled, terrified at his own crime. Sir Arthur Inglewood, however, here again displayed his marvellous skill on behalf of his client by the masterly way in which he literally turned all the witnesses for the Crown inside out.

"Having first got Mr. Andrew Campbell to state positively that in the accused he certainly did not recognize the man in the tweed suit, the eminent lawyer, after twenty minutes' cross-examination, had so completely upset the stockbroker's equanimity that it is very likely he would not have recognized his own office-boy.

"But through all his flurry and all his annoyance Mr. Andrew Campbell remained very sure of one thing; namely, that the lady was alive and cheerful, and talking pleasantly with the man in the tweed suit up to the moment when the latter, having shaken hands with her, left her with a pleasant 'Au revoir! Don't be late to-night.' He had heard neither scream nor struggle, and in his opinion, if the individual in the tweed suit had administered a dose of poison to his companion, it must have been with her own knowledge and free will; and the lady in the train most emphatically neither looked nor spoke like a woman prepared for a sudden and violent death.

"Mr. James Verner, against that, swore equally positively that he had stood in full view of the carriage door from the moment that Mr. Campbell got out until he himself stepped into the compartment, that there was no one else in that carriage between Farringdon Street and Aldgate, and that the lady, to the best of his belief, had made no movement during the whole of that journey.

"No; Frank Errington was not committed for trial on the capital charge," said the man in the corner with one of his sardonic smiles, "thanks to the cleverness of Sir Arthur Inglewood, his lawyer. He absolutely denied his identity with the man in the tweed suit, and swore he had not seen Mrs. Hazeldene since eleven o'clock in the morning of that fatal day. There was no proof that he had; moreover, according to Mr. Campbell's opinion, the man in the tweed suit was in all probability not the murderer. Common sense would not admit that a woman could have a deadly poison injected into her without her knowledge, while chatting pleasantly to her murderer.

"Mr. Errington lives abroad now. He is about to marry. I don't think any of his real friends for a moment believed that he committed the dastardly crime. The police think they know better. They do know this much, that it could not have been a case of suicide, that if the man who undoubtedly travelled with Mrs. Hazeldene on that fatal afternoon had no crime upon his conscience he would long ago have come forward and thrown what light he could upon the mystery.

"As to who that man was, the police in their blindness have not the faintest doubt. Under the unshakable belief that Errington is guilty they have spent the last few months in unceasing labour to try and find further and stronger proofs of his guilt. But they won't find them, because there are none. There are no positive proofs against the actual murderer, for he was one of those clever blackguards who think of everything, foresee every eventuality, who know human nature well, and can foretell exactly what evidence will be brought against them, and act accordingly.

"This blackguard from the first kept the figure, the personality, of Frank Errington before his mind. Frank Errington was the dust which the scoundrel threw metaphorically in the eyes of the police, and you must admit that he succeeded in blinding them — to the extent even of making them entirely forget the one simple little sentence, overheard by Mr. Andrew Campbell, and which was, of course, the clue to the whole thing — the only slip the cunning rogue made — 'Au revoir! Don't be late to-night.' Mrs. Hazeldene was going that night to the opera with her husband —

"You are astonished?" he added with a shrug of the shoulders, "you do not see the tragedy yet, as I have seen it before me all along. The frivolous young wife, the flirtation with the friend? — all a blind, all pretence. I took the trouble which the police should have taken immediately, of finding out something about the finances of the Hazeldene ménage. Money is in nine cases out of ten the keynote to a crime.

"I found that the will of Mary Beatrice Hazeldene had been proved by the husband, her sole executor, the estate being sworn at £15,000. I found out, moreover, that Mr. Edward Sholto Hazeldene was a poor shipper's clerk when he married the daughter of a wealthy builder in Kensington — and then I made note of the fact that the disconsolate widower had allowed his beard to grow since the death of his wife.

"There's no doubt that he was a clever rogue," added the strange creature, leaning excitedly over the table, and peering into Polly's face. "Do you know how that deadly poison was injected into the poor woman's system? By the simplest of all means, one known to every scoundrel in Southern Europe. A ring — yes! a ring, which has a tiny hollow needle capable of holding a sufficient quantity of prussic acid to have killed two persons instead of one. The man in the tweed suit shook hands with his fair companion — probably she hardly felt the prick, not sufficiently in any case to make her utter a scream. And, mind you, the scoundrel had every facility, through his friendship with Mr. Errington, of procuring what poison he required, not to mention his friend's visiting card. We cannot gauge how many months ago he began to try and copy Frank Errington in his style of dress, the cut of his moustache, his general appearance, making the change probably so gradual, that no one in his own entourage would notice it. He selected for his model a man his own height and build, with the same coloured hair."

"But there was the terrible risk of being identified by his fellow-traveller in the Underground," suggested Polly.

"Yes, there certainly was that risk; he chose to take it, and he was wise. He reckoned that several days would in any case elapse before that person, who, by the way, was a business man absorbed in his newspaper, would actually see him again. The great secret of successful crime is to study human nature," added the man in the corner, as he began looking for his hat and coat. "Edward Hazeldene knew it well."

"But the ring?"

"He may have bought that when he was on his honeymoon," he suggested with a grim chuckle; "the tragedy was not planned in a week, it may have taken years to mature. But you will own that there goes a frightful scoundrel unhung. I have left you his photograph as he was a year ago, and as he is now. You will see he has shaved his beard again, but also his moustache. I fancy he is a friend now of Mr. Andrew Campbell."

He left Miss Polly Burton wondering, not knowing what to believe.

And that is why she missed her appointment with Mr. Richard Frobisher (of the London Mail) to go and see Maud Allan dance at the Palace Theatre that afternoon.