The main location of the series is Stockholm, but most of it is shot in Gothenburg.
There are several references to Moomins and Hattifatteners. These are characters from a series of books and a comic strip by Finnish author Tove Jansson. The Moomins are the central characters; the Hattifatteners are secondary ones. The Hattifatteners are unusual characters, and a comparison to them may be taken as derogatory. Several television series and films are based around the Moomins' world.
Season 1 is based on Leif G.W. Persson's novel "Kan man dö två gånger?" and parts of his novel "Den som dödar draken". Season 2 is based on Persson's novel "Den sanna historien om Pinocchios näsa".
Bäckström was previously played by Claes Malmberg in Death of a Pilgrim (2013) and Den fjärde mannen (2014), both of which also feature Kjell Bergqvist in another role.