The case of the West Memphis Three — Damien Echols, Jason Baldwin and Jessie Misskelley, imprisoned as teens in the 1993 murders of three Cub Scouts — has become widely known through the activism of A-list actors and musicians who took up the cause, along with three ‘‘Paradise Lost” documentaries that called the convictions into question.

After seeing that first ‘‘Paradise Lost” film in 2005, filmmaker Peter Jackson ("Lord of the Rings") and wife Fran Walsh stepped in, financing their own investigation and enlisting director Amy Berg (the Academy Award-nominated ‘‘Deliver Us from Evil") to chronicle the convoluted case and the new findings that were uncovered.

‘‘West of Memphis” is nonfiction filmmaking at its best, a film with a fierce point of view yet one that doesn’t pretend to have all the answers or a monopoly on truth. It beautifully blends the detachment of objective observation with the conviction of informed judgment.

‘WEST OF MEMPHIS’ Rated: R Opens today at Kahala 8

Most importantly, it tells a great story, one that surprises, appalls, riles and gratifies, even as it leaves at least as many questions as it resolves.

The case shocked the people of West Memphis, Ark., where 8-year-olds Michael Moore, Steven Branch and Christopher Byers were found naked and hog-tied in a drainage ditch. Two of the boys had drowned, while the third bled to death, his genitals mutilated, evidence prosecutors used to claim they were killed in a satanic ritual.

The suspects were convicted in part on a confession Misskelley later recanted, one filled with conflicting details that critics claim was coaxed and prodded by police interrogators. Baldwin and Misskelley were sentenced to life in prison, while Echols was condemned to death.

After Joe Berlinger and Bruce Sinofsky’s 1996 documentary ‘‘Paradise Lost: The Child Murders at Robin Hood Hills” questioned the prosecution’s case, activists rallied around the suspects. Celebrities jumped in, among them Johnny Depp, Eddie Vedder, Natalie Maines and Patti Smith, who all appear in ‘‘West of Memphis.”

Rallies were held, benefits were staged, appeals were filed. A woman named Lorri Davis began corresponding with Echols, eventually taking the lead in the case and marrying him while he was on Death Row.

Along with Jackson, interviewed extensively in the documentary, and Walsh, Davis and Echols serve as producers on ‘‘West of Memphis,” creating an unusual scenario in which filmmakers are part of their own story, with a stake in the outcome that goes far beyond whether Michael Moore ever gets a sit-down with one of the corporate honchos he pursues.

Unequivocally, the film is on the defendants’ side, characterizing police and prosecutors as either inept, deceitful, or both. Yet Jackson, Berg and their collaborators are nothing but thorough, providing detailed segments with witnesses who now retract testimony that helped convict the defendants and hiring not just one, but half a dozen, of their own forensics experts, who all dispute evidence presented by prosecutors.

‘‘West of Memphis” offers compelling evidence of who might have killed the three boys, though it’s all circumstantial, adding to the infuriating sense of confusion and futility that has persisted in the case for nearly two decades.

After 18 years in prison, Echols, Baldwin and Misskelley were freed in 2011 after entering guilty pleas that allowed them technically to maintain their innocence. It’s a triumphant moment in ‘‘West of Memphis,” one that likely would not have come to pass without the efforts of the filmmakers.

Like many great dramas, it’s an ending that satisfies but also vexes, because the story really isn’t over. The film builds a convincing case for the innocence of the West Memphis Three, but it might take some deathbed confession to know what really happened.

If you believe Echols, Baldwin and Misskelley murdered those boys, then child killers now are out on the street.

If you believe they didn’t do it, then innocent men spent half of their lives in prison, while someone else got away with murder.

The abiding image — photos literally left at the end of the closing credits — is that of the other West Memphis Three, little boys who died horribly, for whom justice has not been served.