For films that otherwise so vividly identified and evoked the trauma visited upon child soldiers, Kim Nguyen’s Oscar-nominated “War Witch” and Cary Fukunaga’s aptly titled “Beasts of No Nation” made a tactful point of avoiding geographical specifics in their otherwise unflinching portraits of Central and West Africa. So it’s among the most valuable virtues of “Wrong Elements” that it almost pedantically pinpoints the precise wheres and whens of its subjects’ suffering. With chunks of onscreen text and title cards, French-American novelist Jonathan Littell’s documentary exhaustively lists the dates and locations marking the rise and still-progressing fall of the Lord’s Resistance Army, the Ugandan rebel movement that fed its ranks for decades by abducting and recruiting thousands of unsuspecting adolescents.

Why do such details matter? Simple as they are, they lend immediacy to events that could well be presented as a kind of waking nightmare — while giving viewers a contextualizing map and timeline underscores just how under-exposed Uganda’s crisis has been relative to contemporary atrocities elsewhere. If Littell’s lengthy, firmly structured but stylistically unadorned doc is sometimes a little pedagogic in its approach, that’s fair enough: It’s unpacking facts that, to many, may be horrifically new. Like Joshua Oppenheimer in “The Act of Killing” and “The Look of Silence,” Littell also invites his human subjects to re-examine violations they’ve already committed or endured. He’s either a less probing or less patient interviewer, however, since “Wrong Elements,” enlightening and moving as it often is, doesn’t amass equivalent moral tension.

“War is supposed to get rid of all the wrong elements in society,” said Acholi spirit medium and rebel leader Alice Auma in 1987 — a quote that opens the film, which is otherwise muted in tone, on a note of bitter irony. For “Wrong Elements” investigates an army that sought not to eradicate corruption, but to foster it across generations — as children, involuntarily indoctrinated into a culture of free killing, grew from victims into perpetrators. What, then, are the parameters of blame or sympathy for those who, taught early to murder without conscience or consequence, amass a kill list as unconsidered as it is long?

Spiritual instruction from on high is what the Acholi people largely accept drove Joseph Kony, then in his twenties, to found the Lord’s Resistance Army as rebellion spread across Northern Uganda following Yoweri Museveni’s divisive ascent to power in 1986. Over 60,000 teenagers were drafted into the LRA over 25 years, with only half that number escaping its clutches alive and receiving amnesty.

The most compelling material in “Wrong Elements” concerns a trio of friends and former LRA conscripts in the city of Gulu — motorcycle taxi drivers Geofrey and Mike, and impoverished mother Nighty — who return to the site of their now-destroyed base camp in South Sudan. Their accounts of the abuse sustained and carried out under the LRA’s control are startling to hear first-hand, with Nighty’s recollections of becoming a 13-year-old bride to Kony himself especially wrenching. (The LRA’s particularly violent mistreatment of female child soldiers is further underlined by reticent interviews with Lapisa Evelyn, a still shell-shocked escapee who alludes to her misfortunes principally through sense memory.)

Even the most hard-up childhood isn’t without moments of levity, however, and the doc finds disturbing poignancy in the friends’ giggling reminiscences of games played and jokes shared in the camp — mutual nostalgia not entirely erased by their mature understanding of their past’s horrifying context. “It was a stupid life,” Geofrey wistfully acknowledges, “but it was also interesting.”

Littell, best-known internationally for his hefty, Holocaust-focused 2006 novel “The Kindly Ones,” has a sensitive ear for succinctly evocative victim testimony. (“I thought they were cutting wood,” recalls a grieving mother whose children were slain by the LRA in her own yard. There’s no way to sentimentalize such interview material.) “Wrong Elements” has less direct impact, however, the further it gazes up the power hierarchy. In the latter half of the film, the trial of Dominic Ongwen — a former commander of the now scattered and depleted LRA, who emerged from hiding to face prosecution for war crimes at the International Criminal Court — is examined in methodical procedural detail, but with no emotionally galvanizing outcome or point of view.

Littell’s degree of official access is impressive, though it’s his incidental observations of rural community life that resonate most here, whether it’s a lone woman sorrowfully shelling pigeon peas or local menfolk garrulously chatting at urban traffic hubs. “Wrong Elements” is shot with a keen eye, but at 133 minutes, it’s edited with a rather less discerning one: Fewer filler images of rippling grass or parading ants would be a start towards tightening things. And while this man of letters, in his first stab at feature-length filmmaking, shows real awareness of what knowledge the camera can independently glean from its subjects, he occasionally pushes too hard for revelations. Asking reformed killers if they can “feel the presence” of their victims feels forced, even a little crass, in a film that successfully draws less coerced moments of cathartic insight from interviewees. As one survivor puts it with a sad shrug: “There is nothing we can do — the only way is to forgive and begin normal life again.”

Cannes Film Review: ‘Wrong Elements’

Reviewed online, London, May 6, 2016. (In Cannes Film Festival — Special Screenings.) Running time: 133 MIN.

  • Production: (Documentary — France-Germany-Belgium) A Jean-Marc Giri, Thomas Kufus, Benoit Roland presentation of a Veilleur de Nuit, Zero One Film, Wrong Men production. (International sales: Le Pacte, Paris.) Produced by Jean-Marc Giri. Co-producers, Thomas Kufus, Benoit Roland.
  • Crew: Directed by Jonathan Littell. Camera (color), Joachim Philippe, Johann Feindt; editor, Marie-Hélène Dozo; sound, Yolande Decarsin, Yves Comeliau; supervising sound editor, Ludovic Van Pachterbeke; re-recording mixer, Ansgar Frerich; visual effects supervisor, Jean-Michel Boublil; visual effects, Automatk VFX; associate producer, Jean-Charles Morisseau; line producer, Tassilo Aschauer.
  • With: Geofrey, Michael, Nighty, Lapisa Evelyn, Dominic Ongwen. (Acholi, Kiswahili, Sango, English dialogue)