I'm not quite sure I agree, Sjöwall and Wahlöö definitely also painted a certain picture. How realistic it is (or was, at the time) I can't say of course, born well after the timeframe the books were written and in a different country. And if you'd like your crime novels without too much political influence then Agatha Christie is definitely a good choice
(although some became political as time passed, like Ten Little *******)
Edit: hmm I can't even put a book title up here without it being starred away....
I was talking about the original title of And Then There Were None.