I didn't give this four stars based on the whodunnit, but on the B storyline that ran since the very first book. This is the climax of the battle between Magdalena and her arch-enemy, a local police officer. This conflict was a major driving force of the series.
There's a definite feeling of finality to this book, which makes me wonder if this was was where Tamar Myers originally intended to stop the series. But, of course, she didn't. She'd drag the series out another ten books, in the good old American tradition of writing a decent book series to death.
If you have been reading the series in order, STOP HERE. If you haven't been reading the series in order, don't go beyond this book. The next book is not only excruciating, Meyers actually insults her readers on the dedication page, commanding readers no longer send her any more title suggestions, since they're "not funny."
One more point -- the series is a parody of life in Pennsylvania Dutch country. It is not supposed to be an accurate reflection of that life. It saddens me that this has to be pointed out, since I've read so many reviews of people disappointed in the inaccuracies. It could be that the reviews themselves were trying to be parodies, but I don't hold out much hope for that.