Illegal immigrants were killed.

Conclusion: The detective finally solved the case, and twelve people admitted the fact of killing themselves, but the detective did not bring them to justice as murderers, but ended the matter with "outsiders climbing the train at night to commit crimes".

Murderer: The murderer was 12 people in the car, and everyone participated in the collective crime.

Extended data:

Murder on the Orient Express is a novel by agatha christie, a British mystery writer. It is one of hercule poirot's series of works and the most famous one.

This work was first published in 1 93465438+1October1year by Collins Crime Club in England, and later in the same year it was published in the United States by Dade Meade Company in the United States with the title "The murder of Calais carriage". This book is widely regarded as one of agatha christie's outstanding and famous works, and has been adapted into movies and stage plays for many times.

References:

Murder on the Orient Express-Baidu encyclopedia