The plan is for Father Lavigny to take wax impressions. Ali then makes clever duplicates.
There are always certain collectors who are willing to pay a good price for genuine antiques and will ask no embarrassing questions.
Father Lavigny will effect the substitution of the fake for the genuine article preferably at night.
And that is doubtless what he was doing when Mrs Leidner heard him and gave the alarm.
What can he do?
He hurriedly makes up a story of having seen a light in the antika-room.
That went down, as you say, very well.
But Mrs Leidner was no fool.
She may have remembered the trace of wax she had noticed and then put two and two together.
And if she did, what will she do then?
Would it not be dans son caractere to do nothing at once, but enjoy herself by letting hints slip to the discomfiture of Father Lavigny?
She will let him see that she suspects but not that she knows.
It is, perhaps, a dangerous game, but she enjoys a dangerous game.
And perhaps she plays that game too long.
Father Lavigny sees the truth, and strikes before she realizes what he means to do.
Father Lavigny is Raoul Menier a thief.
Is he also a murderer?
Poirot paced the room.
He took out a handkerchief, wiped his forehead and went on: That was my position this morning.
There were eight distinct possibilities and I did not know which of these possibilities was the right one.
I still did not know who was the murderer.
But murder is a habit.
The man or woman who kills once will kill again.
And by the second murder, the murderer was delivered into my hands.
All along it was ever present in the back of my mind that some one of these people might have knowledge that they had kept back knowledge incriminating the murderer.
If so, that person would be in danger.
My solicitude was mainly on account of Nurse Leatheran.
She had an energetic personality and a brisk inquisitive mind.
I was terrified of her finding out more than it was safe for her to know.
As you all know, a second murder did take place.
But the victim was not Nurse Leatheran it was Miss Johnson.
I like to think that I should have reached the correct solution anyway by pure reasoning, but it is certain that Miss Johnsons murder helped me to it much quicker.
To begin with, one suspect was eliminated Miss Johnson herself for I did not for a moment entertain the theory of suicide.
Let us examine now the facts of this second murder.
Fact One: On Sunday evening Nurse Leatheran finds Miss Johnson in tears, and that same evening Miss Johnson burns a fragment of a letter which nurse believes to be in the same handwriting as that of the anonymous letters.
Fact Two: The evening before her death Miss Johnson is found by Nurse Leatheran standing on the roof in a state that nurse describes as one of incredulous horror.
When nurse questions her she says, Ive seen how someone could come in from outside and no one would ever guess.
She wont say any more.
Father Lavigny is crossing the courtyard and Mr Reiter is at the door of the photographic-room.
Fact Three: Miss Johnson is found dying.
The only words she can manage to articulate are the window the window
Those are the facts, and these are the problems with which we are faced:
What is the truth of the letters? What did Miss Johnson see from the roof? What did she mean by the window the window?
Eh bien, let us take the second problem first as the easiest of solution.
I went up with Nurse Leatheran and I stood where Miss Johnson had stood.
From there she could see the courtyard and the archway and the north side of the building and two members of the staff.
Had her words anything to do with either Mr Reiter or Father Lavigny?
Almost at once a possible explanation leaped to my brain.
If a stranger came in from outside he could only do so in disguise.
And there was only one person whose general appearance lent itself to such an impersonation.