“That’s the Italian for ‘traitor,’” continued the inspector, “and I got some information from the porter that fits in with that suggestion.  We’ll have him in presently, and you shall hear.”

“Meanwhile,” said Thorndyke, “as the position of the body may be of importance in the inquiry, I will take one or two photographs and make a rough plan to scale.  Nothing has been moved, you say?  Who opened the windows?”

“They were open when we came in,” said Mr. Marchmont.  “Last night was very hot, you remember.  Nothing whatever has been moved.”

Thorndyke produced from his bag a small folding camera, a telescopic tripod, a surveyor’s measuring-tape, a boxwood scale, and a sketch-block.  He set up the camera in a corner, and exposed a plate, taking a general view of the room, and including the corpse.  Then he moved to the door and made a second exposure.

“Will you stand in front of the clock, Jervis,” he said, “and raise your hand as if winding it?  Thanks; keep like that while I expose a plate.”

I remained thus, in the position that the dead man was assumed to have occupied at the moment of the murder, while the plate was exposed, and then, before I moved, Thorndyke marked the position of my feet with a blackboard chalk.  He next set up the tripod over the chalk marks, and took two photographs from that position, and finally photographed the body itself.

The photographic operations being concluded, he next proceeded, with remarkable skill and rapidity, to lay out on the sketch-block a ground-plan of the room, showing the exact position of the various objects, on a scale of a quarter of an inch to the foot—­a process that the inspector was inclined to view with some impatience.

“You don’t spare trouble, Doctor,” he remarked; “nor time either,” he added, with a significant glance at his watch.

“No,” answered Thorndyke, as he detached the finished sketch from the block; “I try to collect all the facts that may bear on a case.  They may prove worthless, or they may turn out of vital importance; one never knows beforehand, so I collect them all.  But here, I think, is Dr. Egerton.”

The police-surgeon greeted Thorndyke with respectful cordiality, and we proceeded at once to the examination of the body.  Drawing out the thermometer, my colleague noted the reading, and passed the instrument to Dr. Egerton.

“Dead about ten hours,” remarked the latter, after a glance at it.  “This was a very determined and mysterious murder.”

“Very,” said Thorndyke.  “Feel that dagger, Jervis.”

I touched the hilt, and felt the characteristic grating of bone.

“It is through the edge of a rib!” I exclaimed.

“Yes; it must have been used with extraordinary force.  And you notice that the clothing is screwed up slightly, as if the blade had been rotated as it was driven in.  That is a very peculiar feature, especially when taken together with the violence of the blow.”