Sundance 2012: Peter Jackson's 'West of Memphis' Trailer (Video)

The documentary produced by "The Hobbit" director details the campaign to get three men exonerated in West Memphis, Ark.

The official trailer for West of Memphis, a Peter Jackson passion project, has been released in advance of the documentary's premiere at the Sundance Film Festival on Jan. 20.

The film, co-produced by Peter Jackson and Fran Walsh, marks a collaboration with the recently freed Damien Echols and his wife, Lorri Davis. Directed by Amy Berg, it uncovers new evidence into the convictions of Echols, Jason Baldwin and Jessie Misskelley Jr. for the 1993 murders of three 8-year-old boys -- Christopher Byers, Steven Branch and Michael Moore -- in the small town of West Memphis, Ark.

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Jackson and Walsh, currently filming The Hobbit, have been campaigning to overturn what they've called “one of the most infamous miscarriages of justice in American history” since 2005, when they helped fund a fresh investigation of the case.

The men, dubbed the West Memphis Three, were released in August after 18 years behind bars. In exchange for their freedom, they agreed to an “Alford plea," which allows them to maintain their innocence but also has a guilty plea entered against them.

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"Seven years ago, Fran and I began this journey with Damien and Lorri, having no idea where it would lead," Jackson said last month. "We now realize that journey is not over, that even though these men have been released from prison -- they are not free. Our hope is that continuing evidence testing and further investigation will lead to the unmasking of the killer of these children and that one day Damien, Jason and Jessie will be exonerated.”

After leaving prison, Echols flew to New Zealand to complete West of Memphis alongside Jackson.