Instruct: Classify Amazon reviews into positive or negative sentiment
Query: rotten mystery: no detecting, a killer with no motive,

I'm really mystified why Caroline Roe chose to write a mystery. She can write nice prose that reads easily, and pleasant characters. But her hero does not detecting, there are no clues, the murderer is revealed completely deus ex machina and is not someone who has appeared in the book until the moment he's revealed -- she breaks the fundamental rules of the genre. Nor do I see why she chose a Jewish character. She obviously has no interest in Jewish anything -- one of the key turns in the plot involves a Jewish girl eating in a monastery. Hasn't Roe ever heard of keeping kosher? And what she does have -- a locked ghetto in medieval Spain -- is inaccurate. The first locked ghetto was Venice in the 1500s. This wasn't fair to the mystery fan, or the historical mystery fan.