But if Felix had acted in this way, it followed that either he was the murderer and wished to get the body to his house to dispose of it there, or else he was an innocent man upon whom the real criminal wished to plant the corpse. This latter idea had been growing in the Inspector’s mind for some time. It seemed to hinge very much on the question, Did Felix know what was in the cask when he met it at St. Katherine’s Docks? Burnley recalled the scene at Scotland Yard when it was opened. Either Felix was an incomparable actor, or else he did not know. Burnley doubted even whether any acting could have been so realistic. He remembered also that Felix’s illness from the shock was genuine. No, he rather believed Felix knew nothing of the corpse and, if so, he must be innocent. The point was one Burnley felt he could not settle alone. They must have medical evidence. But if Felix was innocent, who was likely to be guilty? Who else could have had any motive to kill this lady? What could that motive have been, in any case? He could not tell. No evidence had yet come to light to suggest the motive. His thoughts turned from the motive to the manner of the crime. Strangulation was an unusual method. It was, moreover, a horrible method, ghastly to witness and comparatively slow in accomplishment. Burnley could not imagine any one, no matter how brutal, deliberately adopting it and carrying it out in cold blood. No, this was a crime of passion. Some of the elemental forces of love and hate were involved. Jealousy, most probably. He considered it in his careful, methodical way. Yes, jealousy certainly seemed the most likely motive. And then another point struck him. Surely strangulation would only be adopted, even in the heat of passion, if no other method was available. If a man about to commit a murder had a weapon in his hand, he would use it. Therefore, thought Burnley, in this case the murderer could have had no weapon. And if he had no weapon, what followed from that? Why, that the crime was unpremeditated. If the affair had been planned, a weapon would have been provided. It seemed, therefore, probably that the crime was not deliberate and cold-blooded. Some one, when alone with Madame, had been suddenly and unexpectedly roused to a pitch of furious, overmastering passion. And here again, what more likely to cause this passion than acute jealousy?