Nightmare

I have a question about a ...

Question: I have a question about a movie I saw a long, long time ago. I don't know the name of it, but I do know some details. It is about two girls who, while taking a trip, are stopped by a sheriff who arrests them and sends them to prison. They don't see much of each other while in prison, but when they do, they talk about how they were framed and how they both want to escape. I must note that these girls were pretty, and I think this is why the sheriff arrested them, because in this movie the warden and staff would use the girls in the prison at their own parties, forcing them to wear evening gowns and "entertain" their guests. As the movie progresses, these two girls finally plan a way out. While picking potatoes, they both decide to make a run for the fence or bushes. One girl gets away, but the other gets shot and killed. That is all I know about this movie. I really hope that you can come up with a name for me as I have been looking for a very long time to