The brief scene with the young woman screaming on the bus was shot with a candid camera on a real bus with real passengers. Their reaction to the scream is real.
Not one tripod was used for this movie - everything is shot with hand held camera, unique for the Swedish movie industry at the time of shooting.
Most of the policemen and journalists in the film are played by real policemen and journalists.
Kollberg's baby boy is played by Bo Widerberg's son Johan Widerberg, who later became a professional actor. He utters his first line ever in this movie, the word 'ball'.
Bo Widerberg had seen The French Connection (1971) and wanted to make a Swedish equivalent of that film.