When documentary filmmaker Amy Berg first came across the story of the West Memphis Three, she found the tale utterly compelling.

"It's kind of an intoxicating case, once you start reading about it and hearing about the people," the Oscar-nominated documentarian told CBC's Laura Thompson.

"It's the greatest injustice in the American criminal justice system. It's a travesty. It's a huge miscarriage."

Berg's documentary West of Memphis, now hitting theatres, explores the infamous case of the trio convicted and jailed for the 1993 murder of three children in Arkansas but who were ultimately released in 2011 after years of campaigning to have their conviction overturned.

Berg talked to CBC News about incorporating vast amounts of detail into West of Memphis, hearing crucial new evidence for the first time and her sense of responsibility as a filmmaker working on what was essentially a court case still in progress.

A host of famous faces helped direct attention to the trio's struggle through the years, including singers Henry Rollins and Eddie Vedder, director Peter Jackson and actor Johnny Depp.

Damien Echols, the member of the West Memphis Three who was sentenced to death for the killings, served as a producer on the documentary. He also published a memoir entitled Life After Death.

"There was some brotherly kind of love that was instant," Depp said of his meeting Echols.

"Having been in such close contact with [Echols' wife] Lorri over the last dozen years... to finally see Damian arrive at my house, on my doorstep, well it was quite moving," Depp said at the Toronto International Film Festival in September, where the film screened.

"It's been the most profound gift to see [Echols and his wife] out in the world, living."