“The struggle,” thought the detective, “but was there a struggle?” He looked about the room again, but could see nothing that showed disorder anywhere in its immaculate neatness.  No, there could have been no struggle.  It must have been a quick knife thrust and death at once.  “Not a shot?” No, a shot would have been heard by the night watchman walking the streets near the church.  The night was quiet, the window open.  Some one in the village would have heard the noise of a shot.  And it was not likely that the old housekeeper who slept in the room immediately below, slept the light sleep of the aged would have failed to have heard the firing of a pistol.

Muller took a chair and sat down directly in front of the pool of blood, looking at it carefully.  Suddenly he bowed his head deeper.  He had caught sight of a fine thread of the red fluid which had been drawn out for about a foot or two in the direction towards the door to the dining-room.  What did that mean?  Did it mean that the murderer went out through that door, dragging something after him that made this delicate line?  Muller bent down still deeper.  The sun shone brightly on the floor, sending its clear rays obliquely through the window.  The sharp eyes which now covered every inch of the yellow-painted floor discovered something else.  They discovered that this red thread curved slightly and had a continuation in a fine scratch in the paint of the floor.  Muller followed up this scratch and it led him over towards the window and then back again in wide curves, then out again under the desk and finally, growing weaker and weaker, it came back to the neighbourhood of the pool of blood, but on the opposite side of it.  Muller got down on his hands and knees to follow up the scratch.  He did not notice the discomfort of his position, his eyes shone in excitement and a deep flush glowed in his cheeks.  Also, he began to whistle softly.

Joseph Muller, the bloodhound of the Austrian police, had found a clue, a clue that soon would bring him to the trail he was seeking.  He did not know yet what he could do with his clue.  But this much he knew; sooner or later this scratch in the floor would lead him to the murderer.  The trail might be long and devious; but he would follow it and at its end would be success.  He knew that this scratch had been made after the murder was committed; this was proved by the blood that marked its beginning.  And it could not have been made by any of those who entered the room during the day because by that time the blood had dried.  This strange streak in the floor, with its weird curves and spirals, could have been made only by the murderer.  But how?  With what instrument?  There was the riddle which must be solved.