"Johnnie," said Miss Norman, as William Johnson entered her room in response to a peremptory call on the private-telephone, "Inspector Carfon is to honour us with a call during the next few minutes. Give him a chair and a copy of The Sunday at Home, and watch the clues as they peep out of his pockets. Now buzz off."

William Johnson returned to his table in the outer office and the lurid detective story from which Miss Norman's summons had torn him. He was always gratified when an officer from Scotland Yard called; it seemed to bring him a step nearer to the great crook-world of his dreams. William Johnson possessed imagination; but it was the imagination of the films.

A quarter of an hour later he held open the door of Malcolm Sage's private room to admit Inspector Carfon, a tall man, with small features and a large forehead, above which the fair hair had been sadly thinned by the persistent wearing of a helmet in the early days of his career.

"I got your message, Mr. Sage," he began, as he flopped into a chair on the opposite side of Malcolm Sage's table. "This McMurray case is a teaser. I shall be glad to talk it over with you."

"I am acting on behalf of Sir Jasper Chambers," said Malcolm Sage. "It's very kind of you to come round so promptly, Carfon," he added, pushing a box of cigars towards the inspector.

"Not at all, Mr. Sage," said Inspector Carfon as he selected a cigar. "Always glad to do what we can, although we are supposed to be a bit old-fashioned," and he laughed the laugh of a man who can afford to be tolerant.

"I've seen all there is in the papers," said Malcolm Sage. "Are there any additional particulars?"

"There's one thing we haven't told the papers, and it wasn't emphasised at the inquest." The inspector leaned forward impressively.

Malcolm Sage remained immobile, his eyes on his finger-nails.

"The doctor," continued the inspector, "says that the professor had been dead for about forty-eight hours, whereas we know he'd eaten a dinner about twenty-six hours before he was found."

Malcolm Sage looked up slowly. In his eyes there was an alert look that told of keen interest.

"You challenged him?" he queried.

"Ra-ther," was the response, "but he got quite ratty. Said he'd stake his professional reputation and all that sort of thing."

Malcolm Sage meditatively inclined his head several times in succession; his hand felt mechanically for his fountain-pen.

"Then there was another thing that struck me as odd," continued Inspector Carfon, intently examining the end of his cigar. "The professor had evidently been destroying a lot of old correspondence. The paper-basket was full of torn-up letters and envelopes, and the grate was choc-a-bloc with charred paper. That also we kept to ourselves."

"That all?"

"I think so," was the reply. "There's not the vestige of a clue that
I can find."

"I see," said Malcolm Sage, looking at a press-cutting lying before him, "that it says there was a remarkable change in the professor's appearance. He seemed to have become rejuvenated."

"The doctor said that sometimes 'death smites with a velvet hand.' He was rather a poetic sort of chap," the inspector added by way of explanation.

"He saw nothing extraordinary in the circumstance?"

"No," was the response. "He seemed to think he was the only one who had ever seen a dead man before. I wouldn't mind betting I've seen as many stiffs as he has, although perhaps he's caused more."

Then as Malcolm Sage made no comment, the inspector proceeded.

"What I want to know is what was the professor doing while the door was being broken open?"

"There were no signs of a struggle?" enquired Malcolm Sage, drawing a cottage upon his thumbnail.

"None. He seems to have been attacked unexpectedly from behind."

"Was there anything missing?"

"We're not absolutely sure. The professor's gold watch can't be found; but the butler is not certain that he had it on him."

For some time there was silence. Malcolm Sage appeared to be pondering over the additional facts he had just heard.

"What do you want me to do, Mr. Sage?" enquired the inspector at length.

"I was wondering whether you would run down with me this afternoon to Gorling."

"I'd be delighted," was the hearty response. "Somehow or other I feel it's not an ordinary murder. There's something behind it all."

"What makes you think that?" Malcolm Sage looked up sharply.

"Frankly, I can't say, Mr. Sage," he confessed a little shamefacedly, "it's just a feeling I have."

"The laboratory has been locked up?"

"Yes; and I've sealed the door. Nothing has been touched."

Malcolm Sage nodded his head approvingly and, for fully five minutes, continued to gaze down at his hands spread out on the table before him.

"Thank you, Carfon. Be here at half-past two."

"The funeral's to-day, by the way," said the inspector as he rose and, with a genial "good morning," left the room.

For the next hour Malcolm Sage was engaged in reading the newspaper accounts of the McMurray Mystery, which he had already caused to be pasted up in the current press-cutting book; he gathered little more from them, however, than he already knew.

That afternoon, accompanied by Inspector Carfon, Malcolm Sage motored down to "The Hollows," which lies at the easternmost end of the village of Gorling.

The inspector stopped the car just as it entered the drive. The two men alighted and, turning sharply to the right, walked across the lawn towards an ugly red-brick building, screened from the house by a belt of trees. Malcolm Sage had expressed a wish to see the laboratory first.

It was a strange-looking structure, some fifty feet long by about twenty feet wide, with a door on the further side. In the red-brick wall nearer the house there was nothing to break the monotony except the small wicket through which the professor's meals were passed.

Malcolm Sage twice walked deliberately round the building. In the meantime the inspector had removed the seal from the padlock and opened the door.

"Did you photograph the position of the body?" enquired Malcolm Sage, as they entered.

"I hadn't a photographer handy," said the inspector apologetically, as he closed the door behind him; "but I managed to get a man to photograph the wound."

"Put yourself in the position of the body," said Malcolm Sage.

The inspector walked to the centre of the room, near a highly-polished table, dropped on to the floor and, after a moment's pause, turned and lay on his left side, with right arm outstretched.

From just inside the door Malcolm Sage looked about him. At the left extremity a second door gave access to another apartment, which the professor used as a bedroom.

A little to the right of the door, on the opposite side, stood the fireplace. This was full of ashes, apparently the charred remains of a quantity of paper that had been burnt. On the hearth were several partially-charred envelopes, and the paper-basket contained a number of torn-up letters.

"That will do, Carfon," said Malcolm Sage, as he walked over to the fireplace and, dropping on one knee, carefully examined the ashes, touching them here and there with the poker.

He picked up something that glittered and held it out to the inspector who scrambled to his feet, and stood looking down with keen professional interest.

"Piece of a test tube," remarked Malcolm Sage, as he placed the small piece of glass upon the table.

"Moses' aunt!" gasped the inspector. "I missed that, though I saw a lot of bits of glass. I thought it was an electric bulb."

"Somebody had ground it to powder with his heel, all except this piece. Looks as if there might have been more than one," he added more to himself than to the inspector.

"These are not letters," he continued without looking up.

"Not letters?"

"The paper is all of the same quality. By the way, has anyone disturbed it?" He indicated the grate.

"No one," was the reply.

Malcolm Sage rose to his feet. For some minutes he stood looking down at the fireplace, stroking the back of his head, deep in thought.

Presently he picked up the poker, a massive steel affair, and proceeded to examine the fire-end with great minuteness.

"It was done with the other end," said the inspector. "He must have wiped it afterwards. There was no sign of blood or hair."

Malcolm Sage ignored the remark, and continued to regard the business-end of the poker. Walking over to the door, he examined the fastenings. Having taken a general survey, he next proceeded to a detailed scrutiny of everything the place contained. From the fireplace he picked up what looked like a cinder and placed it in a small box, which he put in his pocket.

The polished surface of the table he subjected to a careful examination, borrowing the inspector's magnifying-glass for the purpose. On hands and knees he crawled round the table, still using the magnifying-glass upon the linoleum, with which the floor was covered. From time to time he would pick up some apparently minute object and transfer it to another small box. At length he rose to his feet as if satisfied.

"The professor did not smoke?" he queried.

"No; but the murderer did," was the rather brusque reply. Inspector Carfon was finding the role of audience trying, alike to his nerves and to his temper.

"Obviously," was Malcolm Sage's dry retort. "He also left his pipe behind and had to return for it. It was rather a foul pipe, too," he added.

"Left his pipe behind!" cried the inspector, his irritation dropping from him like a garment. "How on earth——!" In his surprise he left the sentence unfinished.

"Here," Malcolm Sage indicated a dark stain on the highly-polished table, "and here," he pointed to a few flecks of ash some four or five inches distant, "are indications that a pipe has remained for some considerable time, long enough for the nicotine to drain through the stem; it was a very foul pipe, Carfon."

"But mightn't that have trickled out in a few minutes, or while the man was here?" objected Inspector Carfon.

"With a wet smoker the saliva might have drained back," said Malcolm Sage, his eyes upon the stain, "but this is nicotine from higher up the stem, which would take time to flow out. As to leaving it on the table, what inveterate smoker would allow a pipe to lie on a table for any length of time unless he left it behind him? The man smoked like a chimney; look at the tobacco ash in the fireplace."

The inspector stared at Malcolm Sage, chagrin in his look.

"Now that photograph, Carfon," said Malcolm Sage.

Taking a letter-case from his breast-pocket, Inspector Carfon drew out a photograph folded in half. This he handed to Malcolm Sage, who, after a keen glance at the grim and gruesome picture, put it in his pocket.

"I thought so," he murmured.

"Thought what, Mr. Sage?" enquired the inspector eagerly.

"Left-handed." When keenly interested Malcolm Sage was more than usually economical in words.

"Clean through the left side of the occipital bone," Malcolm Sage continued. "No right-handed man could have delivered such a blow. That confirms the poker."

The inspector stared.

"The sockets of the bolts, and that of the lock, have been loosened from the inside with the poker," explained Malcolm Sage in a matter-of-fact tone. "The marks upon the poker suggest a left-handed man. The wound in the head proves it."

"Then the forced door was a blind?" gasped the inspector.

"The murderer was let in by the professor himself, who was subsequently attacked from behind as he stood with his back to the fireplace. You are sure the grate has not been touched?" He suddenly raised his eyes in keen interrogation.

Inspector Carfon shook his head. He had not yet recovered from his surprise.

"Someone has stirred the ashes about so as to break up the charred leaves into small pieces to make identification impossible. This man has a brain," he added.

The inspector gave vent to a prolonged whistle. "I knew there was something funny about the whole business," he said as if in self-defence.

Malcolm Sage had seated himself at the table, his long thin fingers outspread before him. Suddenly he gave utterance to an exclamation of annoyance.

The inspector bent eagerly forward.

"The pipe," he murmured. "I was wrong. He put it down because he was absorbed in something, probably the papers he burnt."

"Then you think the murderer burnt the papers?" enquired the inspector in surprise.

"Who else?" asked Malcolm Sage, rising. "Now we'll see the butler."

Whilst the inspector was locking and re-sealing the door, Malcolm Sage walked round the building several times in widening circles, examining the ground carefully; but there had been no rain for several weeks, and nothing upon its surface suggested a footprint.