Thanks for the warning not to look up the poem I was going to but did wonder if it would spoil it.
I have picked my culprit, dh has picked his and as he usually gets it right he probably will. However, we are both struggling with how/why they are all somehow linked and my problem is as it is called "and then there were none" I assumed they'd all die so it would be someone we don't know about/haven't seen.
It is very good, nice to watch something that requires a bit of thought and you can't see the ending within the first five minutes.
Also inspired use of a towel
.