Behind the Scenes with the 'Manson Girls'

Charles Manson remains one of America's most notorious murder masterminds -- even 42 years after the infamous killing spree that shocked and terrified the nation. Now, ET goes behind the scenes to examine the new movie that tells the story of the women who devoted themselves to Manson and killed at his command.

The writer and director of Manson Girls, Susanna Lo, said she became intrigued in the story when she discovered a common thread among the girls -- typically a troubled childhood -- that enabled the Manson to capture their minds and hearts while molding them into cold-blooded killers.

Actress Taryn Manning plays Sadie Atkins, who died in prison while serving time for her role in the murders. Manning said she's loved "sinking her teeth into the role," but added that filming has been very intense and some of the graphic scenes actually made her sick.

Monica Keena plays Lynette "Squeaky" Fromme, who was not involved in the murders but was a devoted follower imprisoned for attempting to assassinate then-president Gerald Ford. Keena explains why she thinks Manson was able to exert so much control over his female flock.

Watch the video to also hear actor Bill Moseley talk about playing the notorious killer and to view footage from the set of Manson Girls, which is set to hit theaters in late 2012.