This post is just a reminder for my own use, but since it might be of interest to some readers, I copy and paste from Crime Scraps. Just added to my wish list Lethal Investments by K.O. Dahl, release date: 1 September 2011. I’m looking forward to reading the series in order now, thank you Norman. 
The Gunnarstanda-Frolich series. Norwegian titles and publications dates [with English titles and dates in brackets] Besides the books are translated by Don Bartlett, although the publisher’s pages do not mention it.
- Dødens investeringer (1993) [Lethal Investments 2011]
- En liten gyllen ring (2000) [The Last Fix 2009]
- Mannen i vinduet (2001) [The Man in the Window 2008]
- Lille Tambur (2003)
- Den fjerde raneren (2005) [The Fourth Man 2007]
- Svart engel (2007)
- Kvinnen i plast (2010)
- Isbaderen (2011)
A Crime is Afoot 