The Creation of the Alibi Web
Murder on the Orient ExpressThe conspirators design a complex system of alibis, each passenger vouching for another, to create a closed circle of suspects that seems impossible to break.
increasing
Bearing strength in each event
decreasing
The Design of the Alibis

The Design of the Alibis
The Perfect System
Mary Debenham and Hector MacQueen worked out a system of alibis. Each passenger was paired with another who could vouch for their whereabouts during the critical time. The pairs were chosen so that they appeared to be strangers.
The Pairs
MacQueen and Arbuthnot, Masterman and Foscarelli, Greta Ohlsson and Mary Debenham, and the Count and Countess provided each other's alibis. Others like Hardman and the Princess had alibis from the conductor.
The Purpose
This system was designed to confuse the investigation. If one person was suspected, their alibi partner would confirm their innocence. The web of alibis made it difficult to pinpoint a single culprit.
The Alibis Under Scrutiny

The Alibis Under Scrutiny
The Cracks Appear
Poirot notices that the alibis are too neat. He questions each person, and some inconsistencies emerge. For example, Arbuthnot's pipe-cleaner at the crime scene contradicts his alibi. The Countess's passport alteration suggests she is hiding something.
The Power of the Alibis
Despite the cracks, the alibis hold up under pressure. Each person sticks to their story. The web is strong because the conspirators are committed to the cause. Poirot is forced to find another way.
The Turning Point
When Poirot discovers the shared connection to the Armstrong case, the alibis begin to collapse. He realizes that the alibis are not coincidental but orchestrated. This leads him to the conspiracy theory.
The Collapse of the Alibi Web

The Collapse of the Alibi Web
The Confession
One by one, the passengers confess their true identities. The alibis are revealed as lies. The web that was so carefully constructed falls apart. The conspirators are forced to admit the truth.
The Explanation
Poirot explains that the alibis were designed to protect the group. But when the underlying motive is revealed, the alibis become irrelevant. The truth is more powerful than the lies.
The Aftermath
The conspirators are relieved that the secret is out. They no longer have to pretend. The alibi web, which was their strength, becomes their weakness when Poirot sees through it.
During the planning phase, before the journey
During the investigation, as Poirot questions each person
When Poirot reveals the conspiracy