Master detective Blomkvist was the first film made after one of Astrid Lindgren's books and is a film adaptation of the book of the same name. It was shot in Sala and one of the roles was Sigge Fürst who played a policeman. The children were found through advertising in a weekly newspaper .The film premiered at cinema Astoria in Stockholm on December 20, 1947. Astrid Lindgren realized after this film and the subsequent Pippi Longstocking (1949) that if there were to be any more film adaptations of her books, she wanted to write the scripts herself. And so it was.