Photos of the disappeared at La Verbena Cemetery in Guatemala City. “Finding Oscar” looks at the 1982 Dos Erres massacre. (Ryan Suffern/FilmRise)

There are several parallel stories told in the documentary “Finding Oscar.”

The main one lays out, with traditional means, the horrific circumstances of a 1982 atrocity perpetrated by Guatemalan army commandos against the residents of a small Guatemalan village. Taking its name from the location of the raid, the so-called Dos Erres massacre left 250 civilians dead — many of them unceremoniously dumped down a well, with some thrown in while still alive — by a squad of elite military operatives, known as Kaibiles. The Kaibiles had gone in search of guerrillas they suspected of having recently ambushed government soldiers during the country’s long-running civil war with rural leftist rebels.

The circumstances of that dirty war, epitomized by the events in Dos Erres and their subsequent coverup and painstaking exposure, form the meat of the movie, solidly constructed by American documentarian Ryan Suffern.

Side narratives include one revealing the tacit complicity of the U.S. government, under President Ronald Reagan, in the actions of Guatemalan President Efraín Ríos Montt. But the spotlight shines most brightly on the scientific detective work of Fredy Peccerelli, an anthropologist with the Forensic Anthropology Foundation of Guatemala, whose organization helped identify, through DNA testing, the massacre’s victims.

So who’s Oscar?

The mystery implied by the film’s title concerns a small boy — one of two who were thought to have survived the massacre, yet disappeared — and the search for his current whereabouts. The hunt for Oscar, led by human-rights prosecutor Sara Romero, gives the film its title and spine, along a decidedly personal focus. As it turns out, the urgency of that search isn’t so much because of any testimony that prosecutors hoped to get from Oscar, who remains an enigma for much of the film. The second boy, Ramiro Cristales, is identified much earlier, and his eyewitness account of the slaughter is convincingly harrowing. So are confessions of two cooperating former Kaibiles, whose tales are enough to chill the blood.

But there is an ineffable need for closure, beyond and apart from any prosecutorial purposes, that fuels the film’s pursuit of Oscar. This has more to do with the human impulse to restore broken connections, such as the one between Oscar and his father, who also survived the massacre, by serendipitously accepting a work assignment away from his home village at the time of the raid. This man — who once believed that he had lost his whole family at Dos Erres — says, upon learning that one son may have survived: “I tried to drown my sorrows in alcohol, but my sorrows learned how to swim.”

That’s a deep poetic sentiment, and it powerfully encapsulates the message of hope and wholeness delivered by this well-told tale.

Unrated. At Landmark’s West End Cinema. Contains descriptions of atrocity.

In English and Spanish with some subtitles. 100 minutes.