And Then There Were None---Theme

In this book the theme is "even clever crimes are punished". No mater how canny a murderer may be somewhere sometime someone will bring the justice that was not brought in the house of justice. All the ten characters in the book committed a murderer of some kind, but was never was given the justice that they deserved. That was why they were invited to the island so that they can finally have the sentence that they deserved..... The death sentence.