"You see," pursued the inspector, noting my glance, "he was standing in front of the fireplace, winding the clock. Then the murderer stole up behind him—the noise of the turning key must have covered his movements—and stabbed him. And you see, from the position of the dagger on the left side of the back, that the murderer must have been left-handed. That is all clear enough. What is not clear is how he got in, and how he got out again."
"The body has not been moved, I suppose," said Thorndyke.
"No. We sent for Dr. Egerton, the police-surgeon, and he certified that the man was dead. He will be back presently to see you and arrange about the post-mortem."
"Then," said Thorndyke, "we will not disturb the body till he comes, except to take the temperature and dust the dagger-hilt."
He took from his bag a long, registering chemical thermometer and an insufflator or powder-blower. The former he introduced under the dead man's clothing against the abdomen, and with the latter blew a stream of fine yellow powder on to the black leather handle of the dagger. Inspector Badger stooped eagerly to examine the handle, as Thorndyke blew away the powder that had settled evenly on the surface.
"No finger-prints," said he, in a disappointed tone. "He must have worn gloves. But that inscription gives a pretty broad hint."
He pointed, as he spoke, to the metal guard of the dagger, on which was engraved, in clumsy lettering, the single word, "TRADITORE."
"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."