Original sentence: The "true story" in which the film was based upon involved an Austrian couple who were murdered by three teenagers in their vacation home in The Czech Republic.While claiming to be based on events, the characters in Ils are all fictional
Edited sentence: The "true story" which the film was based upon involved an Austrian couple who were murdered by three teenagers in their vacation home in The Czech Republic.While claiming to be based on true events, the characters in Ils are all fictional