“Ah!” said Holmes. “The fair Georgina! I rather fancied that that was the way your thoughts were tending, old boy. But as a matter of fact she is not quite as irrelevant to the case as you perhaps suppose.”

“Whatever do you mean?”

“I’ll tell you in a moment. I think I hear the heavy tread of regulation police boots!” He knocked out his pipe and sprang to his feet. “I must warn them to avoid obliterating the footprints on the path,” he called over his shoulder as he hurried off to meet them.

A few moments later, he reappeared in the company of four uniformed policemen and a tall, flaxen-haired man whom I recognized at once as our old friend Inspector Gregson, the Scotland Yard detective. He greeted me amiably and we shook hands. “You have arrived very promptly,” I remarked. “Were you already at Beckenham?”

“No, Penge. But I got a message that something was afoot down here, and when I heard that Mr Holmes was involved, thought it would be worth my while to take a look. I’m now officially in charge of the case.” The policeman surveyed the scene for a moment, then he bent down and examined each of the bodies in turn. “This older man seems to have had his skull crushed in at the back,” said he. “This large stone near his head has blood on it, so that appears to be what killed him. This younger man – why, bless my soul! – he’s been shot through the heart!” He stood up and shook his head. “It looks as if there is some kind of homicidal maniac on the loose!”

“I think not,” said Holmes. “Things are not quite as they appear.”

“You don’t think the murderer is likely to strike again?”

“No.”

“You sound very sure.”

“I am. Incidentally, Gregson, the revolver that fired the shot that killed the younger man is over there on the ground, near the edge of the clearing. I have not moved anything, but left it all for you to see.”

The policeman walked over, picked up the pistol and examined it for a moment. “Only one shot discharged,” he said aloud. “I wonder why the murderer left it here for us to find?” He turned to Holmes, with a frown of puzzlement on his features. “What on earth has been happening here, Mr Holmes?” he asked. “Who are these men? What are they doing here, lying dead in the middle of this wood? Who killed them? And what the devil is that noose doing there?”

“I will tell you,” said Sherlock Holmes, “but it will take me a few minutes, so you must be patient.”

Gregson nodded. He dismissed the four constables, instructing two of them to guard the front gate of the cottage and not let anyone in or out, and the other two to perform a similar duty at the gate leading from the back garden to the wood. “And don’t trample down any of those footprints on the path!” he added with a glance at Holmes. “Now, Mr Holmes,” he said, “I am all ears.”

Briefly, then, Holmes described for the policeman Professor Palfreyman’s career, his colleagues at the university and the enduring, if unjustified, guilt the professor had felt for the death of his colleague, John Strange, thirty-odd years previously, which had caused him such mental anguish. He then explained Georgina Calloway’s connection with the professor, how she had come to move into Bluebell Cottage the year before, and the chief incidents during the year, including the arrival in the post of the anonymous letters and the tile. Finally, he mentioned the account that the professor had written for Miss Calloway of what had occurred in Western Macedonia.

“I see,” said Gregson, taking off his hat and scratching his head. “In the light of all that, things are beginning to look a little different. If we try to reconstruct what has happened here, then, it seems that after writing his account for Miss Calloway to read after his death, the professor changed his mind and left it for her to read now. That suggests to me the possibility that he felt he had had enough of life, and had decided to end it. He therefore came here, to what you tell me was his favourite spot in the woods, and rigged up that noose with the intention of hanging himself. It’s a sad business, but not so unusual, if truth be told. A lot of the bodies fished out of the Thames each year are of those who felt they had had enough of life, and had deliberately flung themselves into the river.”

“No doubt. But in this case, of course, the professor did not in fact hang himself, so the analogy with bodies in the Thames does not really apply. What do you make of the presence of the younger man, Timothy Martin?”

“I’m not sure. Do you know anything about the gun that killed him?”

“Not specifically. But Miss Calloway mentioned to us that Professor Palfreyman had a small pocket pistol, which is what that is, so I take it that that is the professor’s.”

“I see. Although, of course, just because the gun is his, it doesn’t prove that he fired it.”

“No,” said Holmes, “but other evidence strongly suggests it. If you examine the professor’s right hand, with your nose as well as your eye, you will detect a strong smell of gunpowder. It is an old gun, and he was using old cartridges, and the powder has leaked backwards out of the chamber. There is a slight burn on his index finger, near where it meets the thumb.”

Inspector Gregson did as Holmes suggested, and after a moment nodded his head. “You are quite right, Mr Holmes. I agree completely. There is a singe mark in the crook of the thumb. Therefore Professor Palfreyman fired the shot that killed Mr Martin. I think we must conclude then,” he continued after a moment, resuming his seat on the log, “that, as Professor Palfreyman was about to hang himself, Martin arrived and tried to dissuade him. But by then, I suppose, the professor was so determined to do away with himself that he resented the other man’s interference, drew his gun and threatened him with it. Martin probably persisted – as anyone would in the circumstances – and the professor lost his temper and shot him. These would-be suicides can be uncommonly determined, you know. Then I think what must have happened is that the burn on the professor’s hand caused him to fling the gun away – which is why it was lying several yards over there – as well as causing him to stagger backwards, trip over and crack his skull on that little rock. Do you agree with that analysis?”

“No. The only part I agree with is that the burn on his hand caused him to drop the gun, and that the burn and slight recoil of the gun may have contributed to his falling backwards. But why did he not break his fall with his hand or his elbow? And although his head undoubtedly struck that stone – the fresh blood on it declares as much – such a blow would not, in my opinion, have caused such a terrible wound as the back of his head displays. But let us leave that for a moment, and consider something else. How was it, do you suppose, that Martin arrived here just as Professor Palfreyman was about to hang himself?”

“I don’t see that as a very important point,” Gregson replied in surprise. “No doubt he called at the house, and someone there told him the professor had taken a walk into the woods, so he followed him and found him about to hang himself.”

“But there was no one in the house then, Gregson. Miss Calloway was in Baker Street, consulting me, and the cook was away visiting her sister in Norwood. The house was empty.”

“Then perhaps seeing that the professor was not at home, Martin guessed where he might have gone to, and came this way.”

“But as I showed you earlier, there was only one set of footprints on the muddy path before we arrived here.”

“Then one of the two men must have come by a different route from the house.”

“There is no other route. There is a fence at the bottom of the garden, and anyone wishing to pass from the garden to the wood must pass through the wicket gate in that fence.”

“Then one of them – Martin, I suppose – must have come not from the house at all, but directly through the woods from the road.”