you work out who the killer / psychopath is half way through the book.
I was very disappointed in Thorn by Vena Cork. I don't think I was even halfway through and I began to think "No, surely not, she can't mean it to be him, that's way too obvious". So I read a bit further and the feeling grew and in the end I just lost interest and did something I hardly ever do - I skipped to the end just to check that I was right (and I was!).
Now I've been reading crime fiction for a long time, so I can forgive an author for not being able to fool me all the time, and I don't mind that as long as the plot is interesting and the characters intriguing, but this was just too easy. I though perhaps there was going to be a huge twist at the end and it was maybe going to be someone else - but no. The author had telegraphed exactly who the nutter was from less than half-way through, leaving nothing to surprise me at the end. A major disappointment.
So, now I'm on The Italian Secretary by Caleb Carr. This is for Reading Group (theme - Sherlock Holmes) and I'm enjoying it so far, but I'm not very far in yet so we shall see how it pans out.