I'm reading a detective series that spans 10 books - it's known as the Martin Beck series and is Swedish. The authors were husband and wife and would write alternating chapters each night after their kids were asleep. They were written during the 60's and are widely credited as writing the first police procedural (rather than relying on the genius of one man/woman detective) novel series.
If you only love gore, shock tactics and lots of violence -- these aren't for you. Much more sedate, pensive and slower in pace. More like Agatha Christie (without the glamour) than Patricia Cornwell.
Might be hard to get hold of if you're not in Europe or the UK, but I think they're worth the look!