It's rare to see a movie that is almost without a fault. This is one of them, although you might have had to have experienced Sweden in the 1980s to get the full impacct - and not to find some of the sub-plots or plot points improbable. The reality behind the movie, as eloquently elaborated on in "Call Girl" (2012) starring Pernilla August, was actually even uglier, and the author of the book - criminology professor and police expert Leif GW Persson - this movie is based on had a pivotal role himself in the real-life scandal.
This paves the way for a great deal of authenticity, and the director Bo Widerberg pours all of his considerable talent into establishing that even further - yes, life really was that bleak, and the score actually *sounds* like the way it all looked and felt.
However, Widerberg adds to that a great deal of suspense and action; a very great deal, even, especially for a Swedish movie of the time. The eerie footage of the villain and his car, for instance, is of Hitchcock class.
Some of the finest actors available in those days also contribute memorable performances. Nobody can tell a whole story through a simple sigh as Tommy Johnsson did; the apparent disillusionment and overwork burden of Andersson is told only by Håkan Serner's fatigued-but-hopeful facial expression, and the walrus-like, condescending fatberg Dahlgren becomes equally likeable and revolting when played by Ernst Günther - not much needs to be said of the mutual dislike between him and the detective heroes.
Speaking of which, Thomas von Brömssen acts out Johansson's heartbreaking backstory with enough subtlety for us to feel it and ache for it without it becoming preachy.
The political dimension of the film also becomes apparent only as the plot unfolds, leading up to... well, let's just say it isn't your standard cop flick.
In short, Widerberg manages to internalise the suspense into his audience, making it ever more powerful than it could have otherwise become.