Who murders ratchet on the orient express

Poirot gave two explanations first, a mysterious figure who came aboard in shadow and left the same way - committing the crime in disguise. and the 2nd which implicated the other 12 who road the train car. He let the owner of the train and the others decided which explanation to give to the authorities upon their arrival. But the most likely was the 2nd which Poirot described in detail. All twelve of the characters who are in the train car are responsible for Rachet's death. The "loquacious" Mrs. Hubbard who orchestrates the gathering of the other 11 to avenge the death of her daughter & grand-daughter is the mastermind. It is alluded to in the comment by of a 12 person jury. The group of the other 11 included, amongst others: the sister, brother in law, the daughters governess, the cook, the godmother and two men who loved the maid who had taken the rap for the kidnapping of Daisy - her father and her sweet heart.