“She wanted to get rid of both of them – her husband and Slade,” Appleby explained later. “Heaven knows why – probably some uncontrolled passion for another man.”
The Sergeant nodded dubiously. “Well, sir, I must admit she looks a bit that sort.”
“Sex-crazy, no doubt. But she has brains as well. She planned the whole thing. And there was more to it than you might think.”
“There was more to it than I can make head or tail of.” The Sergeant was slightly aggrieved. “For instance – ”
“Take it quite simply, and step by step. Mrs Arbuthnot brought Slade home with her at an hour to suit herself. Her husband never really slept before she returned, and so she knew that he would be awake or dozing and hear the sound of voices. She knew that by knocking down the bread bin she could arouse the Ropers and ensure that they heard the sound of voices too. And in that way she would gain the conflicting – and damning – testimony she desired.”
The Sergeant looked increasingly perplexed. “But that’s just where the puzzle lies! The evidence on the voices is conflicting, and you appear to be accepting Arbuthnot’s story. But why disbelieve the Ropers? You haven’t shaken their evidence in the least. And they both swear that the third voice–”
“Was Arbuthnot’s. Well, so it was. But it came from a disk on the gramophone. I found it there before Mrs Arbuthnot had any chance to remove it.”
“Oh, come, sir.” The Sergeant was expostulatory. “That’s an old trick enough. But here it simply doesn’t fit the facts. For Arbuthnot himself, whom it appears we are to believe, swears that he stopped in bed, that from there he heard this third voice, and that it was a strange voice.”
Appleby nodded. “Precisely so. But you will find that the trick does fit the facts. And that it’s not an old trick, but a very new one.
“Consider what Mrs Arbuthnot wanted to contrive: that the Ropers should hear a voice which they knew to be Arbuthnot’s, and that Arbuthnot should hear a strange voice. Once Arbuthnot had told his story, and it appeared to be disproved on the evidence of the unexpectedly wide-awake servants, and she had turned round upon him with her devil’s trick of appearing to see the uselessness of shielding him further and urging him to confess – once she had got him there it would seem there was only the gallows before him. She would be rid of both husband and discarded lover at a stroke. She and the public executioner would have shared the job between them.”
Appleby paused and gazed sombrely round the room. Slade’s body had been lugged away; Arbuthnot had made off to some country retreat; beyond the kitchen the Ropers could be heard packing their trunks. In this expensive setting life had dried up and come to a stop.
“On what, then, did Mrs Arbuthnot’s plan turn? On a very simple psychological fact, well known to anybody who has recorded for broadcasting and had the result played back at him. Under these circumstances a man is utterly unable to recognise his own voice – although, of course, everybody else does so. People have even been known indignantly to deny that these noises could possibly be theirs! Now, Arbuthnot had recently taken to broadcasting, and his wife got hold of a recorded talk – conceivably through Slade himself who had some sort of connection with that sort of thing.
“She brought her victim – her first victim – home and gave him a drink. She went to the kitchen and made enough row to waken the Ropers. She knew that her husband, too, would hear any voices in this room. Then she invited Slade to listen to a bit of the record – perhaps as some particularly choice idiocy of her husband’s. So the Ropers were sure they heard Arbuthnot in this room, and Arbuthnot was equally sure he heard a stranger. Nothing more was required. The moment had come, and she hit Slade hard on the head.”
Appleby paused. “How did I tumble to it? Well, Arbuthnot mentioned that the strange voice had some rather disconcerting quality, and I chewed on that. But the first step was earlier. It was when I saw that we had to do with a premeditated crime, and not with the result of some flare-up of passion on the spot. The poker, you know, must have been thoughtfully provided beforehand, since this room has nothing but that electric radiator.”
And Appleby reached for his hat. “A beastly sterile room, Sergeant, as I said at the start.”