The film-maker Amir Bar-Lev passes his lap-top across the table. He has a message from someone who has just seen his latest film, the multi-layered documentary My Kid Could Paint That. “I believe the child protection authorities should take your child away from you,” the e-mail reads. “You are a pair of sick twisted f***s.”

The pair to which this menacing missive is addressed are Mark and Laura Olmstead, the parents of four-year-old Marla, who caused a sensation in the art world when a gallery in New York State held her first solo exhibition in 2004. Within weeks her elegantly crafted works of abstract expressionism were commanding up to $15,000 a canvas.

Her story was widely reported, and it was a piece in The New York Times that caught the eye of the American documentary film-maker Bar-Lev. “I thought it’d be interesting to look at the debate on modern art,” he says. “Because before I made this film I was sceptical about it and sat firmly in the camp of ‘my kid could paint that’.

“But also I wanted to follow this family as they rode the bucking bronco of fame, like someone who wins the lottery and discovers that it’s not always a positive thing. Finally, I thought it would be interesting to study the media reaction.”

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Bar-Lev realises all these ambitions in his film, although his story found another unexpected dimension. About six months into his project, after Mark and Laura had built their daughter’s reputation via innumerable television and print interviews, the TV show Sixty Minutes ran a story that cast doubt on the authenticity of the young artist’s paintings and suggested that her father helped in their construction.

“My own scepticism about whether she was the sole artist started to surface after I had trouble filming her paint,” continues Bar-Lev. “It didn’t make sense that the Olmsteads would invite me, and then Sixty Minutes, into their home if they had something to hide. But also there are certain things in certain paintings Marla didn’t seem capable of doing. That slowly dawned on me and I didn’t really want it to.”

Bar-Lev’s doubts about the authenticity of the work caused friction with the family, and when the movie showed at the Sundance Film Festival, Laura Olmstead put out a press release saying: “We feel the question of the authenticity of our daughter’s paintings has been answered. Marla has created many pieces on film, one of which, in Mr Bar-Lev’s opinion, was in keeping with her best works. It is our hope that the media will lay the issue to rest at last.” There is little doubt, however, that the painting constructed on film lacks the subtlety and finesse of her earlier, preSixty Minutes work.

“I think [the parents] hoped that the film would exonerate them, and I did too,” Bar-Lev says.

Sadly, that is not the case, and whatever the British public thinks, the Olmsteads are sure to receive one or two more horribly vitriolic letters. Whether they deserve this hostility, only the audience can decide.

My Kid Could Paint That shows at OWE1, Oct 25, 9pm, and OWE2, Oct 26, 3.30pm

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