That’s because Green isn’t really interested in the actors’ performances (although she does include some test footage). She cares more about their opinions on the case, their recollections of the media fracas that ensued at the time, and their theories on who might have killed JonBenét and why. Beyond that, she’s also curious about the actors themselves, and why they might relate to the parts they’re looking to play (particularly the Ramsey parents, whom some suspected of killing their daughter).

Green herself isn’t an actual character in Casting JonBenét. So there’s no explanation for her film’s strange premise, no voice heard from offscreen asking questions of the interviewees, no attempt by her to recap the details of the murder case itself. That’s left entirely to the actors, all of whom have something to say, and the audience, who can piece together the rest of the context pretty easily. This confessional device draws some fascinating digressions from its subjects, while filtering their words through the prism of a national tragedy every American of a certain age likely remembers.

Casting JonBenét takes sad stock of a country, perhaps without meaning to. Its central idea is unavoidably disturbing: that the best way to get these ordinary people to reflect on their lives is by getting them to relate to one of the most infamous murders of recent decades. But, of course, that’s something people do all the time—we’re often pulled into macabre true-crime stories, perhaps because they offer a glimpse into a world we don’t understand, or because we recognize something from our past, or ourselves, in them.

Some of the actors auditioning to play Patsy Ramsey paint her as guilty of murder, or recall being disturbed by her perceived lack of emotion at the time. The women, almost all of them clad in a red outfit Patsy was identified with, speculate on her motivations—anger at JonBenét’s bedwetting, jealousy over her daughter’s success as a beauty-pageant star—while pondering when they get angriest at their own children. One boils with rage at the idea that Patsy felt murderous anxiety simply because she had turned 40; Green then slyly cuts to another actress advancing that theory with the utmost seriousness.

The film’s point is clear: When it comes to crimes of the century, any bystander can turn into a speculative monster. There’s something almost endearing about everyone’s keen awareness of the details of the case, as though they’re obsessives of a science-fiction series. But the death of JonBenét is, of course, jarringly real. Green sometimes hits the laugh lines too hard, but in general does well to maintain the rhythm between the silly and the serious, especially as the actors think about their own lives, and summon stories of abuse, depression, and family strife, in an effort to connect with the characters they might want to play.