A fascinating subject receives a messy, incomplete treatment in “The Wolfpack,” Crystal Moselle’s documentary about a family—Oscar and Susanne Angulo and their seven children (six sons and one daughter)—who have lived a virtually isolated existence in an apartment on Manhattan’s Lower East Side for more than two decades. Though the parents get some of the attention, most is focused on the boys—Mukunda, Narayana, Govinda, Bhagavan, Krisna and Jagadesh—whom their father, a devotee of the Hare Krishna movement, gave ancient Sanskrit names. More significant than what they were called, however, was the fact that Oscar confined them to the apartment for most of their lives. They were homeschooled by Susanne and apparently left the flat only periodically for medical and dental checkups. Otherwise they (along with Susanne and the sole daughter Visnu, who suffers from a medical condition) were locked in by their father, who—along with his wife—say that they took such drastic action to prevent the boys from being contaminated by the degenerate lifestyle in the outside world, with drugs mentioned as an especially prevalent danger.

Had that situation continued indefinitely, of course, there would be no film; Moselle would never have been granted access by Oscar, or even known of the family situation. But at age fifteen Mukunda, as he explains in one of many interview excerpts, rebelled against the isolation by sneaking out onto the streets by himself. His excursion got him arrested, however, because he was wearing a mask modeled after the one worn by serial killer Michael Myers in “Halloween” and frightened passersby. The unusual attire is explained by the dominant facet of the boys’ upbringing—the fact that their connection with the wider society was almost exclusively through the movies they watched and then tried assiduously to recreate on their home turf by fastidiously writing down the dialogue and replaying favorite scenes on their home turf, often donning makeshift costumes. Moselle gives us ample examples of them mimicking bits from pictures like “Reservoir Dogs” and “The Dark Knight” that they’ve apparently committed to memory.

Mukunda’s act of rebellion was the opening that his brothers soon took up, and before long all of them were venturing out, usually as a group and all wearing similar garb—dark trenchcoats and sunglasses. It happened that Moselle noticed them on one of their outings, approached them and struck up a conversation. From that point her relationship with the boys deepened, gradually winning her access to their insular life and the opportunity to document their hesitant but progressive liberation from it. And Susanne joins them in stepping out from Oscar’s complete control.

All of this is interesting and even occasionally moving, but as shot by Moselle and edited by Enat Sidi, it’s presented in a fragmented form that often seems to deliberately withhold background and context until the film can spring them on us for maximum effect and then neglect to address the ramifications. We don’t get much information of Oscar and Susanne’s early life before most of the film has passed, for example, and most importantly, Oscar doesn’t come to the fore until very late in the running-time, though he’s the instigator of the entire scenario. We learn that the Peruvian native and hippie-minded Susanne met while she was traveling in South America, and came to New York in the hope of making money—apparently in the music business—so the family could eventually move to Scandinavia, a region that Oscar, in one of his rambling, nearly incoherent monologues, admires. The plan had no success, and so the family remained in Manhattan.

Oscar might have subscribed to Hare Krishna principles, as the names of his children suggest, moreover, but he was also a heavy drinker, something incompatible with those teachings. Mukunda relates that not working was the form of “rebellion” against society that Oscar embraced, but in fact it merely placed the family at the mercy of that society. For all the talk of the Angulos living an independent existence, they were actually highly dependent on the generosity of others; their apartment was part of the city’s low-cost public-housing program, and presumably Oscar’s ability to buy food (and, obviously, liquor) was based on welfare, since we’re told that the family’s only income derived from the state payments Susanne received for her homeschooling work. There are also occasional allusions to Oscar’s mistreatment of his wife and children, though that aspect of the family’s life is never explored in depth. There’s also reference to a police raid on the Angulo apartment at one point, but again the reasons behind it and any results are glossed over.

Still, for all the film’s omissions and lack of follow-up, the boys are an ingratiatingly articulate, enthusiastic bunch, and one gets a feeling of relief in watching them finally break free of their oddball father’s control and emerging into what is at least a semblance of a more normal life. And it’s good to see Susanne accompany them on their journey into the wider society, even though she still seems to carry a dazed attitude from her years of submission and one can’t escape the nagging feeling that she was, after all, complicit in what her children endured.

At one point in “The Wolfpack,” Mukunda observes that he loves movies so much because they take him to a different world. Moselle’s documentary certainly does that for us non-Angulos. Perhaps inevitably, it can give us only partial access and understanding of that world. More problematically, however, it doesn’t seem even to attempt to organize the material Moselle was able to collect about that little familial universe in the clearest possible fashion. And it certainly fails to address, even peripherally, some extremely important issues about its inner dynamics and its relationship to the outside; one waits in vain for debates that never arise and revelations that never occur. The result is an engrossing portrait of a decidedly peculiar family, but one in which significant pieces of the puzzle are lacking—or summarily ignored.