A really good story! While reading I really badly wanted to guess the killer. And of course I did as I read at the right time: not too early and not too late. I remember in one of Horowitz's videos on how to write mystery stories, he mentioned how the writer should write the story in a way, that the readers could see they could have always guessed the killer but actually not let guess the killer beforehand. Horowitz stay true to his words on his stories. This is my second book of Horowitz )the first was the Magpie Murders) even if I liked both stories, I must say this is my favourite out of the two. 

Even if Horowitz made the detective not do pleasant and sort of a non-hero character, he grew on me towards later. I am sure that character build up was intentional