gives a very strong scent. But they did not. They ignored the body. The inference seems to be that the blood on the knife was not Pratt's blood."
The inspector took off his cap and gently scratched the back of his head. "You're perfectly right, sir," he said. "I'd never thought of that. None of us had."
"Then," pursued Thorndyke, "let us assume that the knife was Pratt's. If so, it would seem to have been used in self-defence. But this was a Norwegian knife, a clumsy tool—not a weapon at all—which takes an appreciable time to open and requires the use of two free hands. Now, had Pratt both hands free? Certainly not after the attack had commenced. There were seven wounds, all on the left side of the back; which indicates that he held the murderer locked in his arms and that the murderer's arms were around him. Also, incidentally, that the murderer is right-handed. But, still, let us assume that the knife was Pratt's. Then the blood on it was that of the murderer. Then the murderer must have been wounded. But Ellis was not wounded. Then Ellis is not the murderer. The knife doesn't help us at all."
The inspector puffed out his cheeks and blew softly. "This is getting out of my depth," he said. "Still, sir, you can't get over the bloodhounds.
