“After the train left Vincovci, did she leave the compartment?”

“No, I am sure she did not.”

“Why are you sure if you were asleep?”

“I sleep very lightly. I am used to waking at a sound. I am sure that if she had come down from the berth above I should have awakened.”

“Did you yourself leave the compartment?”

“Not until this morning.”

“Have you a scarlet silk kimono, Mademoiselle?”

“No, indeed. I have a good comfortable dressing-gown of Jaeger material.”

“And the lady with you, Miss Debenham? What colour is her dressing-gown?’

“A pale mauve aba such as you buy in the East.”

Poirot nodded. Then he asked in a friendly tone: “Why are you taking this journey? A holiday?”

“Yes, I am going home for a holiday. But first I am going to Lausanne to stay with a sister for a week or so.”

“Perhaps you will be so amiable as to write me down the name and address of your sister?’

“With pleasure.”

She took the paper and pencil he gave her and wrote down the name and address as requested.

“Have you ever been in America, Mademoiselle?”

“No. I very nearly went once. I was to go with an invalid lady, but the plan was cancelled at the last moment. I much regretted this. They are very good, the Americans. They give much money to found schools and hospitals. And they are very practical.”

“Do you remember hearing of the Armstrong kidnapping case?”

“No, what was that?”

Poirot explained.

Greta Ohlsson was indignant. Her yellow bun of hair quivered with her emotion.

“That there are in the world such evil men! It tries one’s faith. The poor mother – my heart aches for her.”

The amiable Swede departed, her kindly face flushed, her eyes suffused with tears.

Poirot was writing busily on a sheet of paper.

“What is it you write there, my friend?” asked M. Bouc.

“Mon cher, it is my habit to be neat and orderly. I make here a little chronological table of events.”

He finished writing and passed the paper to M. Bouc.

9.15 Train leaves Belgrade.

about 9.40 Valet leaves Ratchett with sleeping draught beside him.

about 10.00 MacQueen leaves Ratchett.

about 10.40 Greta Ohlsson sees Ratchett (last seen alive). N.B. He was awake reading a book.

0.10 Train leaves Vincovci (late).

0.30 Train runs into a snowdrift.

0.37 Ratchett’s bell rings. Conductor answers it. Ratchett says: “Ce n’est rien. Je me suis trompe.”

about 1.17 Mrs. Hubbard thinks man is in her carriage. Rings for conductor.

M. Bouc nodded approval.

“That is very clear,” he said.

“There is nothing there that strikes you as at all odd?”

“No, it seems all quite clear and aboveboard. It seems quite plain that the crime was committed at 1.15. The evidence of the watch shows us that, and Mrs. Hubbard’s story fits in. For my mind, I will make a guess at the identity of the murderer. I say, my friend, that it is the big Italian. He comes from America – from Chicago – and remember an Italian’s weapon is the knife, and he stabs not once but several times.”

“That is true.”

“Without a doubt, that is the solution of the mystery. Doubtless he and this Ratchett were in this kidnapping business together. Cassetti is an Italian name. In some way Ratchett did on him what they call the double-cross. The Italian tracks him down, sends him warning letters first, and finally revenges himself upon him in a brutal way. It is all quite simple.”

Poirot shook his head doubtfully.

“It is hardly so simple as that, I fear,” he murmured.

“Me, I am convinced it is the truth,” said M. Bouc, becoming more and more enamoured of his theory.

“And what about the valet with the toothache who swears that the Italian never left the compartment?”

“That is the difficulty.”

Poirot twinkled.

“Yes, it is annoying, that. Unlucky for your theory, and extremely lucky for our Italian friend that M. Ratchett’s valet should have had the toothache.”

“It will be explained,” said M. Bouc with magnificent certainty.

Poirot shook his head again.

“No, it is hardly so simple as that,” he murmured again.

“Let us hear what Pierre Michel has to say about this button,” he said.

The Wagon Lit conductor was recalled. He looked at them inquiringly.

M. Bouc cleared his throat.

“Michel,” he said, “here is a button from your tunic. It was found in the American lady’s compartment. What have you to say for yourself about it?”

The conductor’s hand went automatically to his tunic. “I have lost no button, Monsieur,” he said. “There must be some mistake.”

“That is very odd.”

“I cannot account for it, Monsieur.” The man seemed astonished, but not in any way guilty or confused.

M. Bouc said meaningly: “Owing to the circumstances in which it was found, it seems fairly certain that this button was dropped by the man who was in Mrs. Hubbard’s compartment last night when she rang the bell.”

“But, Monsieur, there was no one there. The lady must have imagined it.”

“She did not imagine it, Michel. The assassin of M. Ratchett passed that way – and dropped that button.”

As the significance of M. Bouc’s words became plain to him, Pierre Michel flew into a violent state of agitation.

“It is not true, Monsieur; it is not true!” he cried. “You are accusing me of the crime. Me, I am innocent. I am absolutely innocent! Why should I want to kill a Monsieur whom I have never seen before?”

“Where were you when Mrs. Hubbard’s bell rang?”

“I told you, Monsieur, in the next coach talking to my colleague.”

“We will send for him.”

“Do so, Monsieur, I implore you, do so.”

The conductor of the next coach was summoned. He immediately confirmed Pierre Michel’s statement. He added that the conductor from the Bucharest coach had also been there. The three of them had been discussing the situation caused by the snow. They had been talking some ten minutes when Michel fancied he heard a bell. As he opened the doors connecting the two coaches, they had all heard it plainly – a bell ringing repeatedly. Michel had run post-haste to answer it.

“So you see, Monsieur, I am not guilty,” cried Michel anxiously.

“And this button from a Wagon Lit tunic, how do you explain it?”

“I cannot, Monsieur. It is a mystery to me. All my buttons are intact.”

Both of the other conductors also declared that they had not lost a button; also that they had not been inside Mrs. Hubbard’s compartment at any time.

“Calm yourself, Michel,” said M. Bouc, “and cast your mind back to the moment when you ran to answer Mrs. Hubbard’s bell. Did you meet anyone at all in the corridor?”

“No, Monsieur.”

“Did you see anyone going away from you down the corridor in the other direction?”

“Again, no, Monsieur.”

“Odd,” said M. Bouc.

“Not so very,” said Poirot. “It is a question of time. Mrs. Hubbard wakes to find someone in her compartment. For a minute or two she lies paralysed, her eyes shut. Probably it was then that the man slipped out into the corridor. Then she starts ringing the bell. But the conductor does not come at once. It is only the third or fourth peal that he hears. I should say myself that there was ample time–”

“For what? For what, mon cher! Remember, there are thick drifts of snow all round the train.”

“There are two courses open to our mysterious assassin,” said Poirot slowly. “He could retreat into either of the toilets or – he could disappear into one of the compartments.”

“But they were all occupied.”

“Yes.”

“You mean that he could retreat into his own compartment?”

Poirot nodded.

“It fits – it fits;’ murmured M. Bouc. “During that ten minutes’ absence of the conductor, the murderer comes from his own compartment, goes into Ratchett’s, kills him, locks and chains the door on the inside, goes out through Mrs. Hubbard’s compartment, and is back safely in his own compartment by the time the conductor arrives.”