“What!” cried the colonel. “Do you seriously expect me to believe such nonsense? If that were so, how came he, then, to respond to the other matters included in my letters?”

“Because he that intercepted your letters substituted compositions of his own, which repeated all the remarks you had made on other matters, but omitted every reference to Sarah Dickens. These were the letters that your son received. He did not respond to any questions about Sarah Dickens because he was not aware that you had asked any.”

“That is an utterly fantastic theory!” cried Colonel Reid. “What could anyone hope to gain by such a deception? It would be bound to come to light eventually.”

“Not necessarily. India is never the most peaceful spot in the world, and the north-west provinces in particular have been in uproar. He that interfered with your post no doubt thought it possible that your son would lose his life during his service there, and that the deception would thus never be discovered.”

“And does your theory suggest anyone in particular?” asked Colonel Reid in an ironic tone. “Or is it merely of a general nature?”

“The man responsible is your secretary, William Northcote.”

“What!” cried the colonel.

“How dare you!” said Northcote, his voice trembling with emotion. “That is an outrageous suggestion! I am aware that Reid has employed you to effect a reconciliation between himself and his father, but I could never have imagined that you would stoop so low as this! You seek to achieve your aim by blackening my name without justification!”

“Even if Reid were not killed in India and returned home,” continued Holmes, speaking in a calm voice and ignoring the protests of the other man, “your scheme might still prove successful, you considered, so long as father and son remained estranged, so that the discrepancies between the letters written by the one and those received by the other did not come to light.”

“Nonsense!”

“Fortunately for Captain Reid, he consulted me, and I have been able to discover the truth. After you spoke to us yesterday evening, at the White Hart, you feared that exposure was at hand, which is why you arranged the supposed burglary last night. It was you that broke the window, North-cote, when everyone else in the house was asleep, to make it appear that the theft was the work of an intruder from outside. But there was no intruder. It was you that stole Reid’s private papers, for you wished to prevent his showing the letters to his father.”

“That is a monstrous suggestion!” cried the secretary.

At that moment there came a surprising interruption. Captain Reid himself stepped into the room, carrying in his hand a small leather satchel. I had the impression that he had been waiting for some time outside the doorway, listening to what was being said.

“I have the stolen papers here,” said he, holding up the satchel. “It was in one of the places you suggested, Mr Holmes, hidden at the bottom of Northcote’s wardrobe.”

“It’s a lie!” cried Northcote.

“I will swear to it under oath,” returned Reid. “Besides, why should I lie?”

“To blacken my name further,” cried Northcote, whose face had assumed a pale, sickly hue. “This is slander, gross slander! Gentlemen, I call upon all here present to witness this slander! I shall see this matter settled in court!”

“When my father sees these letters, which he did not write, but which are in an imitation of his hand,” said Reid in a cold voice, “I think it is I that shall be the plaintiff in court and you the defendant, Northcote!”

For a long moment, the secretary said nothing, but looked at each of us in turn as he swayed slightly on his feet. Then, abruptly, he flung himself to his knees in front of his employer and wrung his hands in silent entreaty. “It is true,” he cried at last. “I confess it. In a moment of madness I did it. I destroyed the letter you had written to your son and substituted one of my own, in which I made no reference to Sarah Dickens. I was angry that although he had treated the girl so badly and, as everyone seemed to think, driven her to take her own life, nevertheless the strong bond between father and son still persisted. This seemed to me unfair. Why should he live on happily when the one to whom he had caused so much sorrow had died? But as soon as the letter was sent, I regretted it bitterly. It was a hateful, shameful thing to do. Having falsified one letter, however, I was then obliged to falsify the next. Oh, have pity on me for my shameful actions!”

There was a general shuffling of feet in the room, but no one spoke, and it was clear that no one could think what to say. Captain Reid looked down coldly at the abject figure of his father’s secretary squirming on the floor, and eventually broke the silence.

“I ought to kick you from here to the coast,” said he in a tone of disgust.

“Let me see those letters,” said Colonel Reid abruptly, like a man coming out of a dream.

“One moment,” interrupted Holmes, and the room fell silent once more as everyone turned to see what he would say. “Let us not become too distracted by the matter of the letters. You may see them in a minute, Colonel Reid. But there is a greater crime in question here than the forging of letters: the murder of Sarah Dickens.”

“No!” cried Northcote in a hoarse voice, rising unsteadily to his feet. “It cannot be! Sarah Dickens took her own life. Everyone believes that, save you, Mr Know-all Holmes! I would never have falsified any letters had I thought that the matter was one of murder!”

“If everyone believes that Sarah Dickens took her own life, then everyone is in error. Sarah did not take her own life, and nor was her death an accident: she was murdered. The murderer had planned it coldly and carefully for some time. He had arranged to meet her by the Willow Pool on the afternoon she died. He had, I believe, feigned affection for her, and she no doubt went to meet him expecting to be met with friendship, but the only desire that stirred in his heart was a desire to be rid of someone whose existence was an inconvenience to him. He went to the Willow Pool that day for one reason only, to murder Sarah Dickens in cold blood.”

“Your arguments have been very convincing, Mr Holmes,” interrupted Admiral Blythe-Headley. “Do you have any evidence to lead you to the culprit?”

“I have a witness,” responded Holmes. So saying, he stepped to the open French windows and called to someone in the garden outside. The next moment Mr Yarrow, the vicar, entered, and with him was Noah Blogg.

“Now, Noah,” said the vicar, “tell these gentlemen what you told me earlier.”

The large young man hesitated, and seemed cowed and frightened by the grave faces about him.

“You remember the day you and Harry Cork found the body of Sarah Dickens in the Willow Pool?” said the vicar by way of a prompt. The young man nodded his head dumbly and the vicar continued: “You had seen Sarah earlier that day, had you not, Noah?” Again the young man nodded. “Where had you seen her, Noah?”

“In the shop, sir,” Blogg responded at length. “She came in to buy pegs. She talked to Mother.”

“What did she say?”

“She said she was going to pick blackberries at Jenkin’s Clump. Mother said they were better down the hill a way, and Sarah thanked her and said she’d look down there, too. After she’d gone, Mother said, ‘That girl’s up to something.’”

“Do you know what she meant by that?” asked Holmes.

Noah Blogg shook his head. “No, sir,” he answered.

“Can you think what she might have meant by it, then?”

Blogg appeared confused and did not immediately respond. “Perhaps Sarah was going to meet somebody,” he answered at length.

“Very well. What did you do then?”

“Thought I’d go up the Clump myself and surprise Sarah.”

“And did you?”

The young man nodded his head in a reluctant fashion, as if he would rather not continue.