"There is no witness so sure as the camera," remarked Malcolm Sage as he gazed from one to the other of two photographs before him, one representing him holding an automatic pistol to his own head, and the other in which Sir James was posing as a murderer.

"It is strange that it should be so neglected at Scotland Yard," he added.

Silent and absorbed when engaged upon a problem, Malcolm Sage resented speech as a sick man resents arrowroot. At other times he seemed to find pleasure in lengthy monologues, invariably of a professional nature.

"But we use it a lot, Mr. Sage," protested Inspector Wensdale.

"For recording the features of criminals," was the retort. "No, Wensdale, you are obsessed by the finger-print heresy, quite regardless of the fact that none but an amateur ever leaves such a thing behind him, and the amateur is never difficult to trace."

He paused for a moment; but the inspector made no comment.

"The two greatest factors in the suppression of crime," continued Malcolm Sage, "are photography and finger-prints. Both are in use at Scotland Yard; but each in place of the other. Finger-prints are regarded as clues, and photography is a means of identification, whereas finger-prints are of little use except to identify past offenders, and photography is the greatest aid to the actual tracing of the criminal."

Malcolm Sage never failed to emphasise the importance of photography in the detection of crime. He probably used it more than all other investigators put together. He contended that a photographic print established for all time what the eye could only dimly register for the moment, with the consequent danger of forgetfulness.

As the links in a chain multiplied, it was frequently necessary to refer to the scene of a crime, or tragedy, and then probably some important point would crop up, which the eye had not considered of sufficient importance to dwell upon. By then, in the case of a murder, the body would have been removed, and everything about it either re-ordered or obliterated.

Malcolm Sage proceeded to stuff his pipe with tobacco which he drew from the left-hand pocket of his jacket. He had discovered that a rubber-lined pocket was the best and safest pouch.

He picked up a third photograph and laid it beside the others. It was a print of Mr. Challoner's head, showing, marked in ink, the course of the bullet towards the left of the frontal bone.

"A man shooting himself," began Malcolm Sage, "places the pistol in a position so that the muzzle is directed towards the back of the head. On the other hand, anyone approaching his victim from behind would have a tendency to direct the muzzle towards the front of the head. That is why I got Dawkins to take a photograph of me holding the pistol to my head and of you holding it from behind. These photographs will constitute the principal evidence at the trial."

Sir James nodded. He was too interested to interrupt.

"On this enlargement of the wound," continued Malcolm Sage, "you will see an abrasion on the side nearer the ear, as if the head had suddenly been jerked backwards between the time of the muzzle being placed against the temple and the actual firing of the shot."

Thompson leaned across to examine the photograph.

"If the eyes of someone sitting at a table are suddenly and unexpectedly covered from behind, the natural instinct is to jerk backwards so that the head may be turned to see who it is. That is exactly what occurred with Challoner. He jerked backwards, and the barrel of the pistol grazed the skin and was deflected still more towards the frontal bone."

Sir James and Thompson exchanged glances. Dawkins stood by, a look of happiness in his eyes. His beloved camera was justifying itself once more. Inspector Wensdale breathed heavily.

"Apart from all this, the position of the head on the table, and the way in which the hand was holding the pistol, not to speak of the curve of the arm, were unnatural. You get some idea of this from the photograph that Dawkins took of me, although I could only simulate death by relaxing the muscles. Again, the head would hardly be likely to twist on to its side."

"The doctor ought to have seen that," said the inspector.

Another thing against the theory of suicide was that the second joint of the first finger was pressing against the trigger. Mr. Challoner was an expert shot, and would instinctively have used the pad of the finger, not the second joint.

"The next step," continued Malcolm Sage, "was how could anyone get into the room and approach Challoner without being heard or 'sensed.'"

"He must have been very much absorbed in what he was doing," suggested Sir James.

Malcolm Sage shook his head, and for a few seconds gazed at the photographs before him.

"You will remember there was nothing on the table in front of him. I shall come to that presently. It is very unlikely that a man sitting at a table would not be conscious of someone approaching him from behind, no matter how quietly he stepped, unless that man's presence in the room were quite a normal and natural thing. That gave me the clue to Peters. He is the only person who could be in the library without Challoner taking any notice of him. Consequently it was easy for him to approach his master and shoot him."

"But the locked door, sir," said Thompson.

"That is a very simple matter. An ordinary lead-pencil, with a piece of string tied to one end, put through the ring of the key to act as a lever, the cord being passed beneath the door, will lock any door in existence. The pencil can then be drawn under the door. This will show how it's done." Malcolm Sage reached across for a sheet of paper, and drew a rough sketch.

[Illustration]

"That is why you examined the under-edge of the door?" suggested Sir
James.

Malcolm Sage nodded. "The marks of the cord were clearly defined and reflected in the mirror. Had the key not been touched, it would have helped."

"How?" asked Inspector Wensdale.

"By means of the string the key is turned only just to the point where the lever falls through the hole to the floor. The fingers would turn beyond that point, not being so delicate."

"Mr. Sage, you're a wonder," burst out the inspector.

"I then," proceeded Malcolm Sage, "examined all the other doors in the house, and I found that of one room, which I after discovered to be Peters', was heavily scored at the bottom. He had evidently practised fairly extensively before putting the plan into operation. He had also done the same thing with the library door, as there were marks of more than one operation. Furthermore, he was wiser than to take the risk of so clumsy a tool as a lead-pencil. He used this."

Malcolm Sage drew from his pocket the roll of twine with the thin steel instrument down the centre. It was a canvas-needle, to the eye of which the cord was attached.

"This was absolutely safe," he remarked. "Another thing I discovered was that one lock, and only one lock in the house, had recently been oiled—that of the library-door."

Sir James nodded his head several times. There was something of self-reproach in the motion.

"Now," continued Malcolm Sage, "we come back to why a man should be sitting at a table absorbed in gazing at nothing, and at a time when most of the household are either in bed or preparing for bed."

"Peters said that he was checking his pass-book," suggested Sir
James.

"That is undoubtedly what he was doing," continued Malcolm Sage, "and Peters removed the passbook, put it in a drawer, first destroying the cancelled cheques. He made a blunder in not replacing the pass-book with something else. That was the last link in the chain," he added.

"I don't quite see——" began Sir James.

"Perhaps you did not read of a case that was reported from New York some eighteen months ago. It was very similar to that of Mr. Challoner. A man was found shot through the head, the door being locked on the inside, and a verdict of suicide was returned; but there was absolutely no reason why he should have taken his life.

"What actually happened was that Mr. Challoner went to his bank to draw five hundred pounds with which he hoped to bribe his nephew's fiancÉe. He trusted to the temptation of the actual money rather than a cheque. When he was at the bank the manager once more asked him to return his pass-book, which had not been balanced for several months. He was very dilatory in such matters."

"That is true," said Dane, speaking for the first time.

"That evening he proceeded to compare it with his cheque-book. I suspect that Peters had been forging cheques and he saw here what would lead to discovery. Furthermore, there was a considerable sum of money in the safe, and the quarrel between uncle and nephew to divert suspicion. This, however, was mere conjecture—that trouser-pocket photo, Dawkins," said Malcolm Sage, turning to the photographer, who handed it across to him.

"Now notice the position of those keys. They are put in head foremost, and do not reach the bottom of the pocket. They had obviously been taken away and replaced in the pocket as Challoner sat there. Had he gone to the safe himself and walked back to his chair, the position of the keys would have been quite different."

Instinctively each man felt in his trousers pocket, and found in his own bunch of keys a verification of the statement.

"The whole scheme was too calculated and deliberate for an amateur," said Malcolm Sage, knocking the ashes out of his pipe on to a brass ashtray. "That is what prompted me to get the fingerprints of Peters, so that I might send them to Scotland Yard to see if anything was known of him there. The result you have seen."

"We've been on the look-out for him for more than a year," said Inspector Wensdale. "The New York police are rather interested in him about a forgery stunt that took place there some time ago."

"I am confident that when Challoner's affairs are gone into there will be certain cheques which it will be difficult to explain.

"Then, again, there was the electric light," proceeded Malcolm Sage. "A man about to blow out his brains would certainly not walk across the room, switch off the light, and then find his way back to the table."

"That's true enough," said Inspector Wensdale.

"On the other hand, a murderer, who has to stand at a door for at least some seconds, would not risk leaving on the light, which would attract the attention of anyone who might by chance be in the hall, or on the stairs."

Inspector Wensdale caught Thompson's left eye, which deliberately closed and then re-opened. There was a world of meaning in the movement.

"Well, I'm glad I didn't get you down on a fool's errand, Sage," said Sir James, rising. "I wonder what the local inspector will think."

"He won't," remarked Malcolm Sage; "that is why he assumed it was suicide."

"Did you suspect Peters was armed?" enquired Sir James.

"I saw the pistol under his left armpit," said Malcolm Sage. "It's well known with American gunmen as a most convenient place for quick drawing."

"If it hadn't been for you, Mr. Sage, he'd have got me," said
Inspector Wensdale.

"There'll be a heavy car-full for Tims," remarked Malcolm Sage, as he walked towards the door.