The Red Hand by Arthur Machen

Mr. Phillipps, in spite of all disavowals--in spite of the wall of sense of whose enclosure and limit he was wont to make his boast--yet felt in his heart profoundly curious as to the case of Sir Thomas Vivian. Though he kept a brave face for his friend, his reason could not decently resist the conclusion that Dyson had enunciated, namely, that the whole affair had a look both ugly and mysterious. There was the weapon of a vanished race that had pierced the great arteries; the red hand, the symbol of a hideous faith, that pointed to the slain man; and then the tablet which Dyson declared he had expected to find, and had certainly found, bearing the ancient impress of the hand of malediction, and a legend written beneath in a character compared with which the most antique cuneiform was a thing of yesterday. Besides all this, there were other points that tortured and perplexed. How to account for the bare knife found unstained beneath the body? And the hint that the red hand upon the wall must have been drawn by some one whose life was passed in darkness thrilled him with a suggestion of dim and infinite horror. Hence he was in truth not a little curious as to what was to come, and some ten days after he had returned the tablet he again visited the 'mystery-man', as he privately named his friend.

Arrived in the grave and airy chambers in Great Russell Street, he found the moral atmosphere of the place had been transformed. All Dyson's irritation had disappeared, his brow was smoothed with complacency, and he sat at a table by the window gazing out into the street with an expression of grim enjoyment, a pile of books and papers lying unheeded before him.