makes you think of Paul Bernard and Karla Homolka
Here is a story that is pure non-fiction. There was a Canadian serial killing couple - Paul Bernard and Karla Homolka. After raping and killing many people, they were eventually caught.
Like the chick in this film, Karla claimed that she was abused and was an unwilling partner to Paul's crimes.
Because of her claims, she got a deal and was set free early on. Only later was it found that everything that Paul and Karla did together was filmed on tape and that Karla was far from being an unwilling partner. Unfortunately, the initially made deal was not overturned.
To this day, Paul Bernard is in prison, while Karla Homolka is free.
http://en.wikipedia.org/wiki/Karla_Homolka
http://en.wikipedia.org/wiki/Paul_Bernardo#Other_potential_or_possible_victims