Yoko Ono is suing producers of the movie "Expelled" for using a song without her permission.

The film, which challenges the theory of evolution, uses part of the song "Imagine."

The song asks listeners to imagine a world without religion or faith in an afterlife.

John Lennon's widow has also asked the court to stop filmmakers from distributing the documentary.

The film's producers insist the song is "fair use" and protected under the First Amendment.

One of the professors featured in the movie is Dr. Caroline Crocker.

About four years ago, her contract as a biology professor at George Mason University was not renewed.

Click the play button to watch as Dr. Caroline Crocker discusses the treatment she's received for her beliefs against evolution.