One afternoon about a month after the curious Affair of the Secret Signal, while Geoffrey was busy conducting some experiment in the research laboratory at Chelmsford, a tall, well-dressed young foreigner entered, and advancing to where he was seated, placed his hand upon his shoulder.

“Well!” gasped Geoffrey starting, his face lighting with pleasure. “Why, my dear Enrico! Wherever have you sprung from?”

“They’ve sent me over from Coltano about some new apparatus, and I heard you were in here. I arrived in London a week ago,” explained the dark, smooth-haired young fellow, who was one of the engineers at the powerful wireless station belonging to the Italian Government, and whose messages, prefixed by the call-signal, “I.C.I.,” are so well-known to all wireless men.

Enrico Rossi, the son of a distinguished Italian general, had spent many years in England. He had met Falconer during the war, when they had become fast friends. Rossi had been attached to the Intelligence Branch of the Italian Army, his duty being the interception of enemy messages. Then, after peace, the young man had resumed his responsible post at the great wireless station in Tuscany.

Falconer took off his head-’phones, and learning that his friend was returning to London at half-past five, agreed to accompany him, so that they might dine together at the club.

This they did, and afterwards Geoffrey took his friend along to Mrs. Beverley’s in Upper Brook Street. He had often spoken of Enrico to Sylvia—hence he was anxious to introduce him. The South American widow was one of those many enthusiasts who had fallen beneath the lure of Italy, therefore both mother and daughter made the young man most welcome.

“We are thinking of going to Italy very soon, Mr. Rossi,” said Mrs. Beverley, in the course of their chat in the big, elegant drawing-room. “It is five years since I was there.”

“Oh if you come, please do not fail to let me know,” said the good-looking young fellow, whose elegance of manner was so typically Italian. “I am frequently at our wireless station at San Paolo, outside Rome, and no doubt you will go to the Eternal City.”

“To Florence first, I think, mother,” Sylvia said. “I want to see the Pitti and the Uffizi.”

“Better still,” exclaimed Enrico. “I am within a couple of hours of Firenze—or, as we call it—Firenze la Bella.”

“We are beginning to know quite a lot about wireless through Mr. Falconer,” declared the popular South American hostess. “It is all so intensely fascinating.”

“Yes,” replied the young Italian in very good English. “We are constantly making fresh discoveries. The most wonderful and important nowadays is, of course, telephony through space.”

“We should have all been burned as wizards had we lived a few hundred years ago,” laughed Geoffrey. “The world would have declared us capable of working miracles—heat, motion, light and sound—created out of nothing!”

The young men remained smoking until Geoffrey was compelled to scurry to catch his last train, while Enrico Rossi left him at Liverpool Street Station to go back to his hotel.

“I’ll be down at Chelmsford again to-morrow,” he said on parting. “We’ve got a lot of trouble with our five-kilowatt telephone set, and we want your people to help us out of it.”

“No doubt we can,” laughed Geoffrey. “We can fit you up with most things in wireless at Chelmsford.”

“Right-o!” said the Italian. “I’ll be down in the morning. Buona notte!”

And he turned and left his friend as the train moved off.

Now, on Geoffrey’s return home, he found the Professor busy writing in his study, at work on the great book which was to be the crowning distinction of his splendid career.

The courtly old man put aside his pen, and filling his pipe, listened to his son’s account of the unexpected arrival of Enrico, of whom he had so often spoken since the war, and whose talents as a radio-engineer he always praised so highly.

“I’ll ask him over to dine to-morrow night,” said Geoffrey when at last they rose, for it was then past one o’clock in the morning, and the Professor was about to retire.

Before going to bed, Geoffrey passed into the room which he had converted into an experimental laboratory. It was his habit—as is the habit of most wireless experimenters—to switch on the aerial and listen for a few moments before going to bed.

The long-distance traffic to and from America and Europe is always clearer and of greater interest in the small hours of the morning than in the daytime, for at night the electric waves carry farther, and are converted into signals much louder and more distinct than during the hours of light.

So he took up the telephones, drew down the aerial switch, thus connecting the high twin wires across the lawn to the instruments, and by means of another switch put into circuit his long-wave set—the apparatus upon which the chief high-power European stations were received.

The first he heard was Moscow sending out its usual Bolshevik propaganda—of which nobody takes any notice—then, turning the condenser slowly, he heard Nantes sending to Budapest. Another slight turn and he listened to “F.L.,” (the Eiffel Tower) transmitting upon its continuous wave—or “C.W.,” as it is known to wireless men—to Sarajevo, in Bosnia, and at the same time Madrid was in communication with Poldhu, in Cornwall.

Strange, indeed, is the medley of messages which flash through the ether in the starlight, unseen, unfelt, and undetected, save by the delicate apparatus with its row of little illuminated vacuum tubes such as Geoffrey Falconer had there before him.

He was just about to lay down the telephone when, as he turned the knob of the condenser, he suddenly heard an unusual howl—the strong, high-pitched whistle of a continuous-wave valve. He knew by the sound that it was the wave of a wireless telephone, therefore he waited and listened.

In a few seconds he heard a voice, deep, but not unmusical, exclaim in Italian with great clearness—almost as clear as that from the experimental telephone set at Chelmsford:

“Hulloa! Hulloa! Hulloa! I am calling I.C.I.! Hulloa, I.C.I.! Can you hear me? I.C.I.! I.C.I.!” the voice kept repeating, calling Coltano, in Italy.

Geoffrey was greatly mystified. The note was quite clear and distinct, though the voice was apparently distorted. The modulation was a little faulty. But, as an expert, he knew the great difficulties of telephony without wires, and the thousand and one trivial things which are necessary for success. A loose terminal screw; the disconnection of a single strand of wire no thicker than a human hair; a failing accumulator, or a “soft” valve, all too frequently undetectable, makes the difference between failure and success.

There was an interval of half a minute.

The operator, whoever he was, who wanted Coltano, the station a thousand miles away from Essex, was no doubt making some adjustment.

At last the voice came again with startling clearness.

“Hulloa! Hulloa! Hulloa, Coltano! Hulloa, I.C.I.! Are you on duty, Nicola? Hulloa, Nicola! Nicola? Nicola? Or is it Tozzoni on duty? Tozzoni? Tozzoni? Tanti saluti,” the voice continued. “Listen, Nicola. Here is Enrico Rossi!”

Falconer held his breath. The speech was weird, and quite unusual.

“Rossi calling I.C.I.—calling Nicola. Listen, Nicola, caro mio! Rossi speaking. Rossi speaking. Can you hear me?” continued the distorted voice.

There was a pause. Then again over the carrier-wave of electricity ran the words:

“Listen, Coltano! Listen, Nicola—or Tozzoni! Both of you are my dear friends. Enrico speaking. I am in London—in London! With Falconer, of Chelmsford. Can you hear that?” he shouted in a shriller voice. “With Falconer, of Chelmsford! You know him—both of you. Well, I’m over here in England. But I am not coming back to Italy. My message to you is that I am not returning. I have other plans in America.”

Then there was another pause, during which Falconer listened, silent and breathless.

“Nicola, caro mio! I have other plans in America, so I shall not return to you. Tanti saluti, caro mio. Will you reply? Please reply on six thousand five hundred mÈtres. I will listen. Rossi, changing over!”

Falconer strained his ears to listen to the reply to that amazing message sent by his friend whom only two and a half hours before, he had left at Liverpool Street Station.

But though Madrid, Poldhu, Leafield, Cleethorpes, and Aberdeen were busy to various European stations, he could detect no reply. For quite ten minutes he listened, until, suddenly, the powerful station at Leafield, near Oxford, sent out the words in Morse code:

“Understood—Rossi to Coltano. Good telephony. Cannot hear Coltano.”

Next second another station, which he took to be Aberdeen, sent a message:

“Have understood Rossi to Coltano. What is the mystery? Have not heard Coltano’s reply. Waiting for Coltano.”

But though the young experimenter listened intently the station in Central Italy remained silent.

Suddenly, however, he heard the well-known note of the great Italian radio-station, which tapped out in Morse, after giving his call-signal, “I.C.I.,” the letters “Q.R.A.”—the conventional sign for the question: “What is the name of your station?”

To this there was no reply. Half-a-dozen times the request came from Italy, apparently for the name of the station working telephony, though even that was not clear. Yet, no doubt, a hundred pairs of ears were listening in England alone. At the moment several stations were jamming each other so badly that it became extremely difficult to pick out the words from Coltano.

Again, with almost startling distinctness, the strong, continuous wave of electricity was heard in the telephones, and the same voice spoke:

“This is 2.C.Q., calling I.C.I. Rossi speaking. Glad you got my message. Addio!”

The voice with its foreign accent sounded to Geoffrey much like that of his friend, but being distorted, recognition was not easy.

The whole circumstance was most puzzling, to say the least, and Geoffrey ascended to his room wondering not so much why Enrico had so suddenly made up his mind not to return to Italy as to the identity of the station from which he had transmitted that telephone message across Europe.

The call-signal, “2.C.Q.,” showed it to be an experimental station, but he knew of none so powerful as to be able to transmit telephony to Central Italy.

The whole affair was a complete enigma.

Next day he awaited the arrival of his friend at Chelmsford, but though the hours passed, he did not appear. The following day went by, but he neither came nor wrote. The department at the works with which the station had been doing business was equally puzzled. He had ordered on behalf of the Coltano station a quantity of new apparatus for wireless telephony, and it was being constructed in all haste, yet though a whole week went by, he never returned to inspect it.

To his friend, Frank Boyd, Falconer told the story of that mysterious telephone message in the night. At first Boyd hardly gave it credence, but it was corroborated by the operators at Poldhu, who had been on watch at the time.

“Well, we must find out who ‘2.C.Q.’ is. They have a list of experimenters and their call-signals at Marconi House,” Boyd said. “Let’s ring up and see.”

They did, and the reply received was that the station, 2.C.Q., belonged to a retired naval officer living near Epsom Downs, a man who had experimented in wireless for some years, but whose station was certainly not equipped for long-distance telephony.

Next day Geoffrey came to London, and then went down to Epsom, full of eagerness to solve the mystery. The retired naval commander, a man named Kent, received him, but at once assured him that no telephony had been transmitted from there. He only possessed the ordinary amateur’s set, which he showed his visitor—a limited power of ten watts for continuous-wave transmission. His range of transmission was probably not more than over a ten-mile radius.“Have you any knowledge of a young Italian named Enrico Rossi?” asked Geoffrey, as he stood in Mr. Kent’s wireless room.

“None whatever. To my knowledge I have never heard the name before,” was the reply.

So Geoffrey was compelled to return to London, where, on arrival, he called at the hotel near Charing Cross which Enrico had given as his address, but to his surprise was informed at the bureau that no person of that name had been staying there!

Indeed, Falconer examined the register of visitors himself, but found no entry of the name of Rossi, either in the account-books of the hotel or the register which all visitors signed when engaging rooms.

The mystery of Enrico’s disappearance was, in view of that remarkable wireless message, most curious. Why had the Italian used a false call-signal? Again, from what station had he transmitted that message of farewell?

Having obtained permission, Falconer’s next action was to ask Coltano whether they had received the telephonic message from their engineer on the night in question. The message was sent from Poldhu, while Geoffrey himself, seated at Chelmsford, listened on the big aerial to its dispatch, and then, a quarter of an hour later, heard the reply, which read as follows:

“Poldhu from Coltano. Understood your query. We have heard no telephony and received no message whatever from Enrico Rossi. Why do you ask? Kindly reply.—Director Coltano Radio.”

From that it was instantly plain that the message purporting to be sent to Coltano was upon a low-power set somewhere in the vicinity of London, and not, as Geoffrey had believed, upon apparatus which would transmit two thousand or more miles. The Admiralty wireless station at Cleethorpes heard it, and so had Aberdeen, but there was no proof that it had been heard outside Britain.

The mystery increased hourly. The London police were informed, and inquiries were made concerning the missing Italian.

To Sylvia, Geoffrey had told the whole story, and the girl had become keenly excited concerning the disappearance of the good-mannered young man, who was her lover’s friend.

“If I can help you, Geoffrey, I do hope you will allow me,” she urged. “I believe the poor fellow has met with foul play, and if so, we ought to discover the culprits.”

“That, I regret to say, is my suspicion,” was Falconer’s reply. “I have a keen intuition that there is something very radically wrong somewhere. Why should he announce his departure for America?”

“But he has not sailed, I suppose?”

“The police have been busy examining the list of sailings, but his name does not appear anywhere,” Geoffrey said. “Again,” he went on, “why should he deceive me as to where he was staying?”

“I cannot think why he was not frank and open with you. What had he to fear?” Sylvia remarked.

“That’s just it! Perhaps he went in fear of something, and for that reason kept his whereabouts a secret,” said her lover as they stood together in the pretty morning-room looking out into Upper Brook Street. “Anyhow it’s a mystery which I intend to solve—if possible,” he added.

In order to try to solve it he obtained leave from the works, and travelled first to Pisa, the old marble-built city famous for its cathedral and leaning tower, and then on to Coltano.

The director, a tall, dark-haired, rather handsome man, received him warmly in his private office attached to the long row of buildings which form the power-house and operating rooms of the station.

When he heard the story, he exclaimed in Italian—a language which Geoffrey knew very well:

“All this is most amazing—incredible!” he cried. “Signor Rossi was sent to Chelmsford to obtain certain new apparatus, and in his last report, ten days ago, he wrote that all was in hand, and that he hoped to be back in a fortnight’s time. Why should he go to America?” asked the director, shrugging his shoulders significantly. “I cannot believe it! We can only leave it to the police. He has a brother living in Firenze.”

“Ah, yes!” exclaimed Geoffrey. “I have heard him speak of him. He is an advocate, I think.”

“Yes. A very nice fellow. He lives in the Via Giotto.”

“I will go and see him,” the young Englishman said, and that same night he left for the Lily City.

Next day he called upon the advocate, and made inquiry regarding his brother. Signor Rossi, however, replied that he had heard nothing of him since his departure for London.

Then Falconer retold the strange story of the amazing farewell message, and his subsequent disappearance.

“Can you offer any suggestion concerning the extraordinary precaution he took to mislead me as to where he was staying in London?” inquired Geoffrey.

The advocate reflected.

“He may have been in fear of some enemy or other.”

“Then he had enemies?” asked the Englishman quickly.

“Ah! That I cannot tell. If he had, he never mentioned them to me.”

“Neither did he to me,” Falconer said. “But he was the last man in the world to have enemies, I should have thought. The police have taken up the inquiry, and one of the reasons I am here is to obtain his photograph—if you have one.”

“Fortunately I have a recent one. He sent it to me from Rome six months ago,” answered Enrico’s brother, who produced from a drawer a good cabinet portrait.

“Excellent!” exclaimed Falconer. “We will reproduce it and circulate it as soon as I get back to London. Poor Enrico! There can be no doubt that he has fallen a victim of some very cleverly-conceived plot. I only hope I shall be successful in unravelling it.”

“I sincerely hope so too, signore,” said the advocate, and later on Falconer left him, departing that same day for London, travelling by way of Milan and the Gothard.

On opening the London newspaper, which he bought on Folkestone Pier when he landed, his eyes met a startling headline, and he sat in his corner seat in the boat-train, aghast as he read the amazing announcement.

On the previous day, it was stated, three men from a well-known furniture depository went with the key to a flat in Longton Mansions, Bayswater, to remove the furniture into storage, its owner, Mrs. Priestley, having gone to Buenos Ayres for a year to join her husband, who had an appointment out there.

On entering the flat, they first commenced removing the furniture from the drawing-room and dining-room. Then they cleared out two bedrooms, when one of the men, unlocking the door of a small box-room, the key of which was in the door, was startled at finding a man huddled up inside! A few seconds sufficed to show that he was dead—and had no doubt been dead some days!

At once the police had been called, care being taken to hide the gruesome discovery from other tenants of the flats. The body was brought out, and the detective-inspector of the Division, on seeing it, identified the body as that of a young man named Enrico Rossi, an Italian engineer, who had been reported missing. The report concluded with the usual cryptic assurance that the police had the matter in hand.

Geoffrey sat staggered. His worst fears were now realised. His friend Enrico had, no doubt, been done to death!

On arrival at Victoria Station, he drove at once to Scotland Yard, where he interviewed Superintendent Ransley, the same official with whom the affair of the Secret Signals had brought him into contact. And to him he gave the photograph of the dead man, which he had brought from Italy.

“Yes, Mr. Falconer, the whole circumstances are an enigma,” the superintendent told him as they sat together in the rather barely-furnished room. “We are now in search of the woman named Priestley. Yet as far as I can gather, she is a most respectable lady. Her husband has recently obtained a post as vice-consul at San Cristobal, and she stored her furniture in order to join him.”

“But where is she now?”

“On her way to Buenos Ayres perhaps. I hope to know to-morrow if she has sailed. But whether she has or not, we shall no doubt eventually find her.”

“And arrest her?”

“Yes—providing the coroner’s jury bring in a verdict of wilful murder. And they must, for he was struck a heavy blow on the head by a piece of iron piping.”

Later Falconer stood by the body of his friend, who was dressed just as he had been when they parted at Liverpool Street. Indeed he was still wearing his light overcoat, showing that he had been killed either on arrival at the flat or upon his departure.

Naturally Geoffrey was greatly perturbed, and eager to discover the woman in whose apartment Enrico had been assassinated. Next day the motive of the crime was established—robbery. His wallet was missing! That he had carried one Geoffrey knew, because he had produced it to pay for his railway-fare from Chelmsford to London. It was a dark-red one, and seemed well-filled with Treasury notes.

In due course, the inquest was held, and though Geoffrey gave evidence of identification, he refrained, at the suggestion of Superintendent Ransley, from telling the jury of that remarkable telephonic message of farewell to which he had listened. The jury returned their verdict, and left the police to solve the mystery and arrest the woman Priestley.

But though they made every inquiry, no trace could be found of her. The firm of furniture removers stated that she had called one day and asked them to remove her furniture and store it, handed the key of the flat to the clerk, showed him a receipt for the last quarter’s rent, and gave him a cheque for fifty pounds on account. She told him that she was going abroad, and would probably be away for a year at least. A receipt was given, and the men, going to carry out the work of removal, made the sensational discovery.

About a month went by. The body of poor Enrico had been buried at Geoffrey’s expense, and though the latter continued his research work at Chelmsford, his thoughts were ever centred upon the mysterious Mrs. Priestley.

One day Superintendent Ransley received information that an Englishwoman named Priestley, who answered the description of the missing woman, was staying at the HÔtel des Indes at the Hague. A few hours later a detective-inspector armed with a request for arrest and extradition, left London on his way to Holland via Harwich, and six days later Mrs. Priestley was at Bow Street Police Station, where she was interrogated by Superintendent Ransley, who, of course, first cautioned her that whatever she might say would be taken down and might be used as evidence against her.

The charge that she had been guilty of murdering Enrico Rossi had, it seemed, from the first staggered her. She had protested her innocence over and over again.

“You knew this Signor Enrico Rossi?” said the superintendent, looking up from the pocket-book in which he had been writing.

“Certainly I did—in Italy long ago,” was her reply. “I was born in Italy, though my parents were English, and I first knew him in Ancona when quite a girl.”

“He called to visit you at Longton Mansions?”

“He wrote saying he would call, and asked me to name a day. But I was much engaged, and neglected to write to him. He, therefore, never visited me.”

“Then how came he to be found murdered in your flat?” asked the superintendent coldly.“Ah! That I cannot tell. It is a mystery.”

“Yes,” grunted Ransley, “I agree—it is! But it would not be a mystery if you told me the truth, Mrs. Priestley. You surely cannot expect us to give credence to your denial?”

“I have told the truth,” was the woman’s firm reply. “I have never set eyes upon Enrico Rossi since a month before the war. I then met him in Pisa.”

“Was anyone else in your flat on the night in question?”

“Nobody. My maid, Axford, had gone home to Taunton three days before.”

“What time did you return home on that night?”

“I had been to a dance, and it must have been nearly three o’clock before I got back. Now that I recollect, I am horrified to think that I actually slept in the flat within a few feet of the dead body of the man I had known so well.”

“Yes,” remarked Ransley in his curious cold tone of disbelief. “Quite naturally.”

Then a few minutes later the woman who had denied all knowledge of the affair was sent back to her cell, and the superintendent gave orders for her to be brought before the magistrate next morning and charged with the murder of Enrico Rossi.

This was done, and the evening newspapers were full of the sensational affair, though, owing to certain circumstances, it was not deemed wise by the authorities to let the public know the exact problem. Hence the case was camouflaged. There were certain interests at stake which apparently puzzled even the Home Office.

Eva Priestley, represented by a well-known Bow Street solicitor, who offered no defence, was remanded. Her husband was communicated with, but he knew nothing, and was, no doubt, astounded at the discovery, and mystified regarding the young man Rossi.

A week later the prisoner, a tall, fair-haired woman, whose photograph, in due course, appeared in all the picture-papers, and whom readers of this present narrative must well remember under another name, was committed for trial at the Old Bailey upon the capital charge, the Public Prosecutor alleging that she had enticed the young fellow to her flat, and had murdered him for the contents of his wallet.

Geoffrey Falconer agreed with Superintendent Ransley and with the eminent King’s Counsel who prosecuted. The admission of Mrs. Priestley that she and Enrico were old friends was surely most damning evidence.

Not until several days after Mrs. Priestley had been sent for trial was a curious fact noticed concerning the blue serge jacket which poor Enrico wore at the time he lost his life. Inside the collar the tab, bearing the name of the tailor in Rome who had made the suit, had been hastily cut aside, and beneath it a slit had been made, apparently with a sharp knife. But whether this had been done during Rossi’s lifetime or after death could not be established.

One of the strangest features of the affair, however, was that weird message by radio-telephone—a message spoken, no doubt, by one aware of the fact that Enrico had been done to death. The police inquiries, however, failed to elicit any proof that the woman suspected of the crime had any connection with anybody acquainted with wireless, even in its most amateur form.

Obsessed by the mystery, Geoffrey had many conversations concerning it with Sylvia, who believed in Mrs. Priestley’s innocence notwithstanding the chain of circumstantial evidence and the fact that the body had been hidden in her flat. But if Mrs. Priestley had not murdered the young man, who had? asked the Public Prosecutor.

The day fixed for the trial of the alleged murderess was approaching, when one afternoon Geoffrey, revisiting unexpectedly the scene of the tragedy as he had done several times, chanced to pass on the stairs a short, lean, white-haired little man who was ascending to the flat above. Their eyes met, and the old man, turning his head, quickened his pace.Geoffrey recollected having met him before in those days when Venice was seriously threatened by the Austrian advance. His name was Nocera, and he was a banker in Venice—a man of considerable repute. Why, Geoffrey wondered, was he living at Longton Mansions?

Of the hall-porter he later on learnt that Mr. Nocera and his wife had occupied the flat above Mrs. Priestley’s for about three months. They came from Italy and took it furnished. After a month they had as guest a Mr. Zuccari, described by the hall-porter as a tall, thin, athletic man, with a black moustache and very bald head.

“He was something of a mystery, and I was very glad when he left,” the man declared. “One day, indeed, I found him trying the door of Mrs. Priestley’s flat with the latchkey of the flat above. I caught him unexpectedly, and he certainly did not like it, for three days later he left, and I haven’t seen him since.”

“That’s curious,” Falconer remarked. “Very curious! Was he really trying to get into her flat?”

“It seemed to me that he was. But, of course, my presence prevented him.”

Later that evening Geoffrey related to Superintendent Ransley what he had learnt, but strangely enough the Venice banker and his wife left early next morning, taking with them two good-sized trunks. To the porter they remarked that they were going to Edinburgh, but the man was pretty wide awake, and giving the taxi-driver a quiet hint, heard from him an hour later that he had driven them to Victoria, to the Continental train.

Quickly observation was kept upon the pair, and at Folkestone the passport which they presented as Italian subjects was declared by the passport officer to be out of order, a fact which necessitated them both returning to London, though quite unconscious that they were under suspicion.

At the same time, after closely questioning the hall-porter, Superintendent Ransley gave instructions that active search should be made for the bald-headed guest who had been tampering with the lock of Mrs. Priestley’s flat. Then there was a further surprise, and Mrs. Priestley herself, questioned in prison, admitted she knew the people in the flat above, and being Italians, they had once or twice visited her. At once the police, aided by Geoffrey, redoubled their efforts, Falconer being at last successful in obtaining a further piece of curious evidence. He had taken the key of Mrs. Priestley’s flat to a number of locksmiths in order to ascertain if they had been asked to make a similar key, but in vain. Of a sudden, however, he recollected having seen a barrow full of old keys and rusty locks in Lower Marsh, Lambeth, and upon it a notice bearing the words: “Keys cut at shortest notice.”

To the owner of the barrow he showed the key. The man—an artist in his profession—examined it long and carefully, until he found scratched upon it in tiny figures a number. He referred to a book, and then replied:

“Yes, I cut a duplicate of this for a tall, thin gentleman. He was a foreigner, I remember.” And he gave the date, three days before the disappearance of Enrico Rossi.

This was a very valuable link in the chain of fresh evidence, and the police very wisely allowed the supposed Venice banker and his wife to leave for Paris, entirely unsuspicious of the fact that they were being closely watched. The day came for the trial of Mrs. Priestley, but it was postponed.

Meanwhile two English detectives were in Paris watching Nocera and his wife, information from Venice concerning the “banker” having been the reverse of reassuring.

Within three weeks Superintendent Ransley’s expectations were rewarded. The man Zuccari visited them at their hotel in the Rue Castiglione!

From that moment Zuccari was never left, and four days later all three were arrested in the street near the Opera by six agents of the SÛretÉ.

Madame Nocera was released, but her husband, in order to save himself, made a statement to Inspector Peyron when taken to the bureau of police. In a great state of agitation he admitted that, while posing as a banker in Venice, the money he possessed belonged to the Austrian Government—in fact, he was the paymaster of the spies of Austria scattered through northern Italy during the war. He declared that he had had no hand whatever in the assassination of Enrico Rossi.

The French police were, however, far from satisfied with this statement, and pressed him, under threats, for further information. It then became apparent that Nocera and Zuccari had quarrelled over their share of the spoils, and in the end Nocera explained the ingenious plot to Inspector Peyron and the two men from Scotland Yard.

It had become known to Zuccari that Enrico Rossi was to be sent on business from the Coltano wireless station to England, and that he intended to call upon Mrs. Priestley, his old friend. The flat above the latter’s being to let furnished, the Noceras took it, and succeeded in cultivating friendly relations with the lady below. Then Zuccari arrived from Italy, and on one of his visits with Nocera to Mrs. Priestley, he succeeded in getting hold of the latchkey of the flat used by the servant. Of this he had a duplicate made in Lower Marsh, and then he waited in patience.

Enrico arrived in London and wrote to Mrs. Priestley. She quite innocently mentioned this fact to Nocera, and said that she could not see him as she was going away.

This was their opportunity. Entering the flat in Mrs. Priestley’s absence, Zuccari discovered Enrico’s letter, and his address at a small private hotel at Kensington.

He ascertained that Mrs. Priestley would be out at a dance on a certain evening; therefore he telegraphed in the lady’s name asking Enrico to call at half-past ten o’clock for supper.

After leaving Falconer at Liverpool Street station, Enrico had therefore taken a taxi direct to Longton Mansions, where Zuccari was already in Mrs. Priestley’s flat awaiting him. On entering there the unsuspecting young Italian was struck down, his wallet taken and his jacket removed. From a little pocket behind the silk address-tab of the tailor, Something was extracted—a tiny book of thin India paper.

That Something was of the greatest value to the murderer, and was the motive of the crime, for it contained the secret wireless code of the Italian Government, both military and diplomatic, and would be of inestimable value to the Austrians and Germans, even though peace had now been declared.

Having secured that for which he had cunningly plotted, Zuccari had replaced the coat upon the inert body of the man he had beaten to death with a piece of iron piping, put on his overcoat, and then locked him in the small box-room, afterwards leaving the flat. Three hours or so later Mrs. Priestley returned, all unconscious of the tragedy, and slept there for the last night before her departure abroad.

The London police, two days after the true facts had been ascertained in Paris and Mrs. Priestley had been released, visited the flat occupied by Nocera, for, on inquiry, they had elicited the fact that, as secret agent of Austria in Venice, he had had much technical instruction in the use of wireless.

In the flat was found quite a powerful generating plant, with a very up-to-date telephone set, and a most ingenious aerial arrangement by which one could transmit upon quite a long wave-length. Why this had originally been installed was obscure, but it was believed to be one of the powerful secret sets used by German spies in London during the war.

In any case, it was proved that the reason Enrico had not given his correct address was because he had apprehensions of some sinister attempt. It was also proved that Zuccari had, after the tragedy, spoken into the microphone that weird message to which Geoffrey had listened, and which proved such a remarkable feature of the affair. The message of farewell had apparently been the curious fancy of the unscrupulous assassin.

The stolen code-book was recovered three days after Zuccari’s arrest from his baggage at the left-luggage office at Brussels, whence it was his intention to convey it to Germany. The Italian Government, who had two years before issued warrants for the arrest of both Zuccari and the traitor Nocera, at once claimed their extradition, and both men are now serving a sentence of solitary confinement for life—a doom worse, indeed, than the gallows.