Clean Reads discussion

I read And Then There None By Agatha Christie a little while ago and I enjoyed it very much, but I am confused about something. I still can't find out who the killer is. At the end of the book, I didn't remember the last person who killed themselves to be in the situations where they had killed everybody else. Agatha Christie also didn't give any clues at all as to how she was the one responsible for all those murders. It is something that is very perplexing to me. Does anyone know how she went on to commit those crimes or who did?

Does your copy have a little post-script thing entitled "A manuscript document sent to Scotland yard by the master of the Emma Jane, fishing trawler"? It's by the murderer explaining his/her methods.

You should read that and see if things start to make sense. But, if you would like me to spell it out it's... (view spoiler)[Mr. Justice Wargrave (hide spoiler)].