"Kind of amateur he must have been," he said pityingly. "To leave a thing like that."

Then he swung out into the road.

It was the day after the crime. Tommy and Tuppence were still at the Grand Hotel, but Tommy had thought it prudent to discard his clerical disguise.

James Reilly had been apprehended, and was in custody. His solicitor, Mr. Marvell, had just finished a lengthy conversation with Tommy on the subject of the crime.

"I never would have believed it of James Reilly," he said simply. "He's always been a man of violent speech, but that's all."

Tommy nodded.

"If you disperse energy in speech, it doesn't leave you too much over for action. What I realise is that I shall be one of the principal witnesses against him. That conversation he had with me just before the crime was particularly damning. And in spite of everything, I like the man, and if there was anyone else to suspect, I should believe him to be innocent. What's his own story?"

The solicitor pursed up his lips.

"He declares that he found her lying there dead. But that's impossible, of course. He's using the first lie that comes into his head."

"Because, if he happened to be speaking the truth, it would mean that our garrulous Mrs. Honeycott committed the crime-and that is fantastic. Yes, he must have done it."

"The maid heard her cry out, remember."

"The maid-yes-"

Tommy was silent a moment. Then he said thoughtfully:

"What credulous creatures we are, really. We believe evidence as though it were gospel truth. And what is it ready? Only the impressions conveyed to the mind by the senses- and suppose they're the wrong impressions?"

The lawyer shrugged his shoulders.

"Oh! we all know that there are unreliable witnesses, witnesses who remember more and more as time goes on, with no real intention to deceive."

"I don't mean only that. I mean all of us-we say things that aren't really so, and never know that we've done so. For instance, both you and I, without doubt, have said some time or other 'There's the post,' when what we really meant was that we'd heard a double knock and the rattle of the letter box. Nine times out of ten we'd be right, and it would be the post, but just possibly the tenth time it might be only a little urchin playing a joke on us. See what I mean?"

"Ye-es," said Mr. Marvell slowly. "But I don't see what you're driving at?"

"Don't you? I'm not sure that I do myself. But I'm beginning to see. It's like the stick, Tuppence. You remember? One end of it pointed one way-but the other end always points the opposite way. It depends whether you get hold of it by the right end. Doors open-but they also shut. People go upstairs, but they also go downstairs. Boxes shut, but they also open."

"What do you mean?" demanded Tuppence.

"It's so ridiculously easy, really," said Tommy. "And yet it's only just come to me. How do you know when a person's come into the house? You hear the door open and bang to, and if you re expecting anyone to come in, you will be quite sure it is them. But it might just as easily be someone going out."

"But Miss Glen didn't go out?"

"No, I know she didn't. But someone else did-the murderer."

"But how did she get in, then?"

"She came in whilst Mrs. Honeycott was in the kitchen talking to Ellen. They didn't hear her. Mrs. Honeycott went back to the drawing-room, wondered if her sister had come in and began to put the clock right, and then, as she thought, she heard her come in and go upstairs."

"Well, what about that? The footsteps going upstairs?"

"That was Ellen, going up to draw the curtains. You remember, Mrs. Honeycott said her sister paused before going up. That pause was just the time needed for Ellen to come out from the kitchen into the hall. She just missed seeing the murderer."

"But Tommy," cried Tuppence. "The cry she gave?"

"That was James Reilly. Didn't you notice what a high pitched voice he has? In moments of great emotion, men often squeal just like a woman."

"But the murderer? We'd have seen him?"

"We did see him. We even stood talking to him. Do you remember the sudden way that policeman appeared? That was because he stepped out of the gate, just after the mist cleared from the road. It made us jump, don't you remember? After all, though we never think of them as that, policemen are men just like any other men. They love and they hate. They marry…

"I think Gilda Glen met her husband suddenly just outside that gate, and took him in with her to thrash the matter out. He hadn't Reilly's relief of violent words, remember. He just saw red-and he had his truncheon handy…"