I saw this film on my university campus when it came out in the late 70s. For the time, it was a technical landmark, entirely shot from a subjective camera POV (For an example of a failure of this technique, see the 1946 adaptation of Raymond Chandler's LADY IN THE LAKE). I loved the film, not just for its technical bravura, but for its disturbing tone and intriguing narrative. I don't want to give anything away, but I just loved the way these amoral, aethical bastards seemed to love the work they did. And the film seems impossible to find! How films like this one escape critical acclaim is beyond me - I met Roger Ebert at a film festival in Virginia back in 2000 and stumped him on this one, even though I wasn't trying to. DEFINITELY check Dossier 51 out if you're a fan of thought-provoking films!
