Well, one can question the reality of some scenes and solutions, but on the other hand, the narration is based on true events, so it is not a fully constructed stuff. The characters are quaint, yet evolving, and their actions and ideas emanate from the (painful) past. The mood is well captured, enhances by flashbacks and environment, and apart from tragic/dramatic scenes, there are ones making your giggle... At last but not least - the roundup of the crime is neither regular nor desitive.
As to the performances, they are good/excellent, and unlike many Swedish crime series, the number "frequent participants" is smaller than usual (apart from Thomas W. Gabrielsson perhaps). Robert Gustafsson, usually a comedian, is a convincing detective here with complex past (he won the Swedish Kristallen Award for this), and many from the supporting cast are worth following (Ia Langhammer, Ville Virtanen, among others).
8.5 means 9 points here. Good work!
PS Season 2 is somewhat tardy, but interesting twists in "finals" elevate the less thrilling start.