I passed my hand over my brow. “My head is in a whirl,” I remarked; “the more one thinks of it the more mysterious it grows. How came these two men⁠—if there were two men⁠—into an empty house? What has become of the cabman who drove them? How could one man compel another to take poison? Where did the blood come from? What was the object of the murderer, since robbery had no part in it? How came the woman’s ring there? Above all, why should the second man write up the German word Rache before decamping? I confess that I cannot see any possible way of reconciling all these facts.”

My companion smiled approvingly.