Looking for a mystery on par with ‘And Then There Were None’

I love Agatha Christie’s ‘And Then There Were None’. I’ve read many of her other books but none of them have quite the same appeal.

Can you suggest for me a similar mystery where a group of people are isolated somewhere and there is danger around every corner. Looking for paranoia/suspense and a book that has me constantly theorizing and paying attention to every detail.

It doesn’t have to be realistic either, so if it has Sci-Fi, Fantasy, or Horror elements, that is also great.

Thanks!