LOS ANGELES — Shortly after last year's Academy Award nominations were announced, the filmmaker Tommy O'Haver and the actress Catherine Keener met at Venice Beach to discuss a project inspired by a dark and troubling event.

Keener had already read and turned down the script but had continued to think about it. "So we sat on the beach and talked," O'Haver recalled. "And at one point she said, 'I'm really scared to do something like this.' And I said, 'I have to tell you, I'm scared, too. In some ways I think that's why we have to do it."'

By summer, cameras were rolling on "An American Crime," starring Keener as Gertrude Baniszewski, who provoked and participated in a heinous 1965 slaying that shook the Midwest. O'Haver was a co-writer and the director of the film, which will have its premiere Friday at the Sundance Film Festival.

To this day, the acts that occurred within the Baniszewski (pronounced ban-uh-SHEF-ski) home — where the 16-year-old Sylvia Likens was tortured and killed — remain as shocking as they are unfathomable. Which is why O'Haver so wanted Keener, whose low-key performance as the author Harper Lee in "Capote" had just won her an Oscar nomination.

"It would have been easy to take this story over the top," he said in a phone interview. "So I purposely pulled back. My mantra was 'restraint, restraint, restraint."'

Keener recalled her apprehension about portraying the woman who instigated the killing. "As a mother I said to myself, 'I can't do this.' Later, I thought: 'I'm a mother. I kind of should."'

Like Keener, the film's backers see it not so much as entertainment as an exploration of the human dark side. "Our focus will be on the fact that it's a relevant true story that even affects people today. And on the film as a performance piece," said Henry Winterstern, chief executive of First Look Studios, which financed, produced and will soon be marketing and distributing the film.

Winterstern said representatives from the California chapter and national office of Prevent Child Abuse America had been invited to see the movie and to provide feedback.

Winterstern suggested the Canadian actress Ellen Page ("Hard Candy") for the role of Likens. From her home in Halifax, Nova Scotia, the 19-year-old Page recalled her first reading of the script. "I was just blown away and could hardly believe it was a true story," she said. "I remember literally just going on the computer and staying up all night and reading everything I could." She added: "It just, like, splintered my heart."