“Regrettably, it must be admitted that men and women do sometimes murder those with whom they have been affectionate, but not usually so quickly as in this instance, and we must suspect that the true motives in this case have not yet come to light. What does seem very likely, however, is that Northcote’s involvement with Sarah Dickens was not quite as it appears, and that any display of affection on his part was feigned merely to ensure her silence for a few weeks until he could seal her lips permanently. That he did feign some affection is suggested, I believe, by a page which has been cut from her exercise book of poems: it has been very neatly removed with a pair of nail scissors, and we must suppose it was done by the girl herself. The page is nowhere in evidence now – I have questioned John Dickens on the point – so we may further suppose that she gave it to Northcote. Very likely, that cold and heartless man feigned an interest in her poetry, as he had feigned an interest in the girl herself, and requested it. She would have been flattered by this request, not realizing that he wanted the page only to have a sample of her handwriting from which to prepare the note he intended to leave in Jenkin’s Clump when he had murdered her. If that page ever turns up among his papers, incidentally, I’ll warrant that it contains no instances of the letter ‘f’.”

“You speak of Northcote wishing to ensure her silence,” interrupted Reid in a tone of some puzzlement, “but about what, pray?”

“Something she knew about Northcote himself,” replied Holmes, “something he did not wish anyone to know. It is a point, I admit, which exercised my mind for some time until I hit upon a solution. For how could a local peasant girl like Sarah Dickens learn anything of significance about a man such as Northcote, who occupied a station far removed from her experience and knowledge?”

“It does seem a trifle unlikely,” concurred Reid.

“Indeed; unlikely, but not impossible. It seems to me probable – although here I stray into the realm of conjecture – that this whole business began on the day that Sarah fainted from the heat when picking apples in the orchard here, an incident that Mr Yarrow described to me. If you will recall, Captain Reid, you helped carry her to the house.”

“I remember it well. We brought her into this very room, through the French windows, and laid her on the couch in the corner there.”

“So I understand. Mr Yarrow further mentioned that she was attended by the housekeeper. Now, let us suppose that the housekeeper, having satisfied herself that the girl was comfortable and in no danger of a further attack, had left her alone here for a time. Let us further suppose that, by chance, your father’s secretary happened to enter this room during the period the girl was lying here alone. He would not have known she was here, and she would not yet be fully recovered, so would be lying quite still. Under the circumstances, it is not impossible that he would have failed to see her. His view of the couch as he entered the room would have been partly obscured by this little table and the large vase upon it, and his thoughts would perhaps have been absorbed by his reason for entering the room.”

“What was that, do you suppose?” queried Reid.

“Perhaps to do something which he did not wish anyone to witness,” replied Holmes. “He may have intended to examine or abstract some private papers of your father’s in the desk over there. He would know that you and your friends were all out of the house, working in the orchard, and thus would not interrupt him.

“We may further conjecture that, as he was engaged upon his secret, furtive work, something, some slight movement of the girl’s, perhaps, caused him to look up, and he saw, no doubt to his very great alarm, that she was watching him.”

“I cannot see why the girl’s presence should have caused him any great alarm,” protested Reid. “After all, she could not have appreciated that he was engaged in anything underhand or dishonest.”

“Perhaps not,” returned Holmes. “But knowledge of his own guilt can have a powerful and disturbing effect upon a man’s reason and judgement. The result is not infrequently mental panic, and the conviction that others know more than they in fact do. The panic that would have gripped Northcote at such a moment would have arisen as much, therefore, from his own sense of guilt as from the girl’s presence. He would have seen only that, should she have chosen to do so, Sarah Dickens could have exposed his shameful dishonesty to the world, and this threat would have loomed above every other consideration in his mind. He is, however, a very cunning and deceitful man, and I have little doubt, therefore, that he spoke in a friendly and flattering manner to the girl, and perhaps in the course of the conversation, made an arrangement to meet her again in a few days’ time. That, I suggest, is how the connection between the two of them began. The girl was young and no doubt appeared impressionable. It must have seemed no difficult task to an educated man like Northcote to turn her head and manipulate her affections. On his side the arrangement would have been one of expediency only, a way to gain a little time until he could dispose permanently of the threat that he considered she posed to him. We may imagine he began at once to plan the removal of that threat.”

“It still seems scarcely credible,” I interjected, “that anyone would so swiftly contemplate murder in such circumstances.”

“Perhaps so, Watson, but we do not yet know the extent of Northcote’s dishonesty. Perhaps his hidden crimes are yet greater than I have supposed. He may have been so deeply mired in deceit that he could see no other way out. Nor do we know the true nature of his character. Perhaps, despite the quiet and reserved appearance he presents to the world, he is a man easily moved to violence when his plans are thwarted. The annals of crime are full of such men. I have myself known several.”

“But surely he could have found some other way to prevent the girl speaking of what she had seen,” I persisted. “He could simply have dismissed the matter as of no consequence, for instance, and hoodwinked the girl in that fashion.”

“Perhaps he attempted such a stratagem,” returned Holmes, “and met with no success. Perhaps the girl said something, which indicated to him that she understood all too well the nature of what she had witnessed, and made it clear that any further attempts at deception on his part would be unavailing. As I have frequently had cause to observe, the simplest of people can have surprisingly accurate intuitions as to the motives and character of others. What seems likely, anyway, is that however agreeably he may have spoken to her, and however flattered she may have been by his attentions, she still, nevertheless, considered that she had some hold over him, and was disagreeably pressing in her attentions.”

“Why do you say that?” asked Reid.

“I feel certain that the window that was broken shortly before your departure for India was broken by Sarah Dickens herself. You blamed it on village boys who had been playing in the orchard earlier, but I always thought that unlikely: the broken window was that of the upstairs study, which is on the opposite side of the house from the orchard. I think it more than probable that Sarah, anxious to hear when she would see Northcote again, endeavoured to communicate with him by throwing pebbles up at the lighted window of the study, in which she knew he would probably be working. Unfortunately, we must suppose, her throw was a little over-vigorous.”

“What you are suggesting, then,” said Reid after a moment, “is that Northcote has been swindling my father in some way?”

“I think it highly probable. It is by far the most likely motive for the crime. The account you gave me last week of your family’s affairs suggested that Northcote had advanced quite quickly after his arrival here from simply being your father’s amanuensis to a position of greater confidence and intimacy. I believe he found the temptation to abuse that position too great to resist.”