The day before it happened, they'd been having tea with a neighbor. He was by way of dabbling in herbs and home-brewed medicines.
Among his patent brews was one of coniine - spotted hemlock.
There was some talk about it and its deadly properties.
"The next day he noticed that half the contents of the bottle were gone.
Got the wind up about it.
They found an almost empty bottle of it in Mrs Crale's room, hidden away at the bottom of a drawer."
Hercule Poirot moved uncomfortably. He said,
"Somebody else might have put it there."
"Oh, she admitted it to the police.
Very unwise, of course, but she didn't have a solicitor to advise her at that stage.
When they asked her about it, she admitted quite frankly that she had taken it."
"For what reason?"
"She made out that she'd taken it with the idea of doing herself in.
She couldn't explain how the bottle came to be empty - nor how it was that there were only her fingerprints on it.
That part of it was pretty damning.
She contended, you see, that Amyas Crale had committed suicide.
But if he'd taken the coniine from the bottle she'd hidden in her room, his fingerprints would have been on the bottle as well as hers."
"It was given him in beer, was it not?"
"Yes.
She got out the bottle from the refrigerator and took it down herself to where he was painting in the garden.
She poured it out and gave it to him and watched him drink it.
Everyone went up to lunch and left him - he often didn't come in to meals.
Afterward she and the governess found him there dead.
Her story was that the beer she gave him was all right.
Our theory was that he suddenly felt so worried and remorseful that he slipped the poison in himself.
All poppycock - he wasn't that kind of man!
And the fingerprint evidence was the most damning of all."
"They found her fingerprints on the beer bottle?"
"No, they didn't - they found only his - and they were phony ones.
She was alone with the body, you see, while the governess went to call up a doctor.
And what she must have done was to wipe the bottle and glass and then press his fingers on them. She wanted to pretend, you see, that she'd never even handled the stuff.
Well, that didn't work.
Old Rudolph, who was prosecuting, had a lot of fun with that - proved quite definitely by demonstration in court that a man couldn't hold a bottle with his fingers in that position!
Of course, we did our best to prove that he could - that his hands would take up a contorted attitude when he was dying - but frankly our stuff wasn't very convincing."
"The coniine in the beer bottle," Poirot said, "must have been put there before she took it down to the garden."
"There was no coniine in the bottle at all.
Only in the glass -" Depleach paused - his large, handsome face suddenly altered - he turned his head sharply.
"Hullo," he said. "Now, then, Poirot, what are you driving at?"
Poirot said,
"If Caroline Crale was innocent, how did that coniine get into the beer?
The defense said at the time that Amyas Crale himself put it there.
But you say to me that that was in the highest degree unlikely - and for my part I agree with you.
He was not that kind of man.
Then, if Caroline Crale did not do it, someone else did."
Depleach said with almost a splutter,
"Oh, damn it all, man, you can't flog a dead horse.
It's all over and done with years ago.
Of course she did it.
You'd know that well enough if you'd seen her at the time.
It was written all over her!