Casting JonBenet lets ordinary people share their wildest murder theories – and the result is deeply unsettling

The second thing to say is that it is deeply unsettling.

I was not familiar with the ins and outs of the JonBenét Ramsey case when I began watching this Netflix feature-length documentary – after all, I was four years old in 1996 (younger than the victim) and grew up a long way away from America, where the murder case attracted such lurid fascination.

So making sense of Casting JonBenet was initially a struggle – and I don't think I'll be the only one, at least in the UK.

The details of the case only drip out bit by bit, and in no particular order, as each actor tries to explain what they think happened. There's speculation – but there's no actual establishing of the facts of the murder investigation. Confusing.

An example: one actor mentions "pineapple" in passing, and it's only after googling the case that I realise what they are actually talking about. A recent reinvestigation of the case revealed traces of pineapple were found in JonBenét's system and her brother's fingerprints were identified on a bowl of pineapple left on the kitchen table, seen by some as evidence that her older brother Burke was involved. But you wouldn't know that context from the programme.

Then there's a series of professional Santa Clauses auditioning and talking about working with children, but without the context that her neighbour played Santa Claus and was once considered a suspect, this makes no sense. Later developments with DNA evidence are barely mentioned.

But – and it's a big but – this show really has nothing to do with discovering the "truth" about what happened that horrible night between Christmas and Boxing Day in 1996, when a little girl was bludgeoned and strangled and left under a white blanket in the basement.

It has little to do with whether Patsy Ramsey was guilty because her handwriting matched the ransom note that initially made everyone think this was a kidnapping, or whether there was a child abuse angle involving a Santa or the girl's father John Ramsey, or whether the parents were covering for nine-year-old Burke. Other documentaries have tried and failed to definitively pin the blame, sometimes provoking defamation lawsuits.

As these weird auditions and reenactments continue, it begins to dawn: this is actually about the public, about us, about how we come up with our own explanations when we can never really know.

We meet these actors who want to play the parents and policemen and paedophile suspects, and they're a really ordinary bunch of Americans from Colorado.

"I'm not a professional actress, but I have been in pageants in 1982, 1983, 1984," one says with pride. In fact, very few of them are anything more than amateur actors. They are mothers, fathers, ex-felons, psychologists, police officers, "sex educators", grocery store meat managers, songwriters.

Some of them do have vague connections with the Ramsey family; some lived up the road in Boulder when the murder happened; some say they felt compelled to audition by a sense of "public service". But none of them have any real knowledge of who killed JonBenét Ramsey.

So what's the point? What's the point in dressing them up as Patsy and John and sticking them in front of the cameras? What's the point in asking these amateur actors whether their character did it?

The point is this: each of these actors, when they put themselves into a character's shoes, has an explanation that comes from their own reality. Because in a high-profile crime like this, the public become obsessive amateur sleuths, examining the evidence and deciding who's guilty (the UK's own experience with the case of Madeleine McCann makes that clear).

And so we learn from the "sex educator" (S&M specialist) that, in his opinion, the lacerations on the child's body had to be sexual. One childless prostate cancer sufferer puts forward his theory that Patsy's eventual death from ovarian cancer was a physical manifestation of her guilt, seeing as her daughter originally came from her womb. The grown-up daughter of an abusive father tells the camera about how secretly violent men can seem like pillars of the community.

A John actor talks about how he and his friends could easily have murdered each other by mistake (did Burke do it?), while a Patsy actress admits to fury at her young child for peeing around the house (JonBenét's mother reportedly was incensed by her bedwetting). They're just trying to understand, to climb inside the heads of their characters, but their own pasts are in there too.

The thing is, we may never know. The evidence was compromised, the clues are confusing. The case remains unsolved, and it most likely will always remain unsolved. In the meantime, all these different horrific explanations – some plausible, some improbable – coexist.

And so producers take that to its logical conclusion, and fill up a reconstruction of the house with Patsys and Johns and Burkes and JonBenéts all simultaneously acting out what could have happened as if in parallel universes.

There are tearful Patsys, evil Patsys, molesting Santas, complicit Johns, guilty Burkes, and there is a lot of shouting and sobbing and screaming. As a finale to a peculiar documentary about the realities we conjure up when we really don't know the truth, it kind of works.

The only reservations I have are about the child actors playing Burke, who thankfully aren't asked for their gory murder theories (though they are asked about their relationship with their sisters). Instead, all the little Burkes are given flashlights and asked to bash watermelons to pieces, presumably to see whether a nine-year-old boy could cave a kid's head in without help. One succeeds, and pops a bit of watermelon into his mouth with a smile. Gratuitous?

But all the little JonBenéts in their pageant outfits, eating biscuits as they have their make up applied – they do have a purpose.

Why was the public so obsessed with this case? Partly it was the enigma, the strange details, the clues. But partly it was the fact that this child was a pageant star, an American beauty, a strikingly beautiful blonde little girl who never got to grow up. So the show closes with JonBenét herself, dancing on an empty stage to a Bernie Wayne song:

There she is, Miss America
There she is, your ideal
With so many beauties
She'll take the town by storm
With her all-American face and form

Casting JonBenét is released on Netflix on Friday 28th April