Murder On The Orient Express By Agatha Christie Report by Ryder Schwartz
After the murder, Poirot begins interviewing the passengers of the Orient Express in private to figure out how likely it is that they were involved.
After finishing up the interviews, Poirot consults Dr. Constantine and M. Bouc to hear what they have to say. Neither can say with confidence who committed the murder.
After going back to his room and thinking deeply about it and reviewing the information once more, Poirot decides to pay the Count and Countess a visit.
After much interrogation and back and forth the couple admits that they changed their names to make sure that they would not be linked to Ratchett's (Cassetti's) murder due to their relation to Daisy Armstrong.
After deep thought and once more reviewing the information Poirot realizes something.
He realizes that McQueen, an employee of Ratchett, had to be involved as it was the only way he would know that the notes and letters were burned.
After heading to meet Dr. Constantine and M Bouc, Poirot reports the new information and then realizes that the Princess had to be lying: she said she could not remember the name of the Countess. It was as though she was trying to hide something...
After many minutes of silence, Poirot tells Bouc to gather the passengers.
Poirot informs the passengers that he has two theories: One, that someone boarded the train in the Balkans and then left before the train departed, or two, that everyone except for the Countess had some involvement in the murder and that they chose to have the Count and Countess appear to be the obvious scapegoat. Mrs. Hubbard reveals the second theory is true; she was the grandmother of the person Ratchett (Cassetti) murdered years ago.